WEB 2.0

1.0 INTRODUCTION

Web 2.0 is both a usage and a technology paradigm. It’s a collection of technologies, business strategies, and social trends. Web 2.0 is more dynamic and interactive than its predecessor, Web 1.0, letting users both access content from a Web site and contribute to it. Web 2.0 lets users keep up with a site’s latest content even without visiting the actual Web page. It also lets developers easily and quickly creates new Web applications that draw on data, information, or services available on the Internet. Web 2.0 isn’t just a new version of the same old Web, it’s a different thing in several ways.

Web 2.0:

• facilitates flexible Web design, creative reuse, and updates;

• provides a rich, responsive user interface;

• facilitates collaborative content creation and modification;

• enables the creation of new applications by reusing and combining different applications on the Web or by combining data and information from different sources;

• establishes social networks of people with common interests; and

• supports collaboration and helps gather collective intelligence.

Wikipedia defines Web 2.0 as “a term describing changing trends in the use of World Wide Web technology and web design that aims to enhance creativity, information sharing, and collaboration among users.” There is huge amount of disagreement among internet experts on what Web 2.0 is and how the term is defined. Some say that Web 2.0 is a set of philosophies and practices that provide Web users with a deep and rich experience. Others say it's a new collection of applications and technologies that make it easier for people to find information and connect with one another online. A few journalists maintain that the term doesn't mean anything at all, it's just a marketing ploy used to hype social networking sites.

The Web 2.0 concepts have led to the development and evolution of web-based communities and hosted services, such as social-networking sites, video sharing sites, wikis, blogs, and folksonomies. The term became notable after the first O'Reilly Media Web 2.0 conference in 2004. O'Reilly Media is an American media company established by Tim O'Reilly that publishes books and web sites and produces conferences on computer technology topics. Although the term suggests a new version of the World Wide Web, it does not refer to an update to any technical specifications, but to changes in the ways software developers and end-users utilize the Web. According to Tim O'Reilly, “Web 2.0

is the business revolution in the computer industry caused by the move to the Internet as platform, and an attempt to understand the rules for success on that new platform.” O'Reilly Media publisher Dale Dougherty coined the phrase Web 2.0.

Some technology experts, notably Tim Berners-Lee, have questioned whether one can use the term in any meaningful way, since many of the technology components of Web 2.0 have existed since the early days of the Web. In September 2005, Tim O'Reilly posted a blog entry that defined Web 2.0. The explanation spanned five pages of text and graphics illustrating O'Reilly's take on what the term meant. O'Reilly's philosophy of Web 2.0 included these ideas

· Using the Web as an applications platform

· Democratizing the Web

· Employing new methods to distribute information

Web 2.0 websites allow users to do more than just retrieve information. They can build on the interactive facilities of "Web 1.0" to provide "Network as platform" computing, allowing users to run software-applications entirely through a browser. Users can own the data on a Web 2.0 site and exercise control over that data. These sites may have an "Architecture of participation" that encourages users to add value to the application as they use it. This stands in contrast to very old traditional websites, the sort which limited visitors to viewing and whose content only the site's owner could modify. Web 2.0 sites often feature a rich, user-friendly interface based on Ajax, openlaszlo, Flex or similar rich media. The sites may also have social-networking aspects.

The characteristics of Web 2.0 are: rich user experience, user participation, dynamic content, metadata, web standards, scalability, openness, freedom and collective intelligence by way of user participation – all should be viewed as essential attributes of Web 2.0. In fact web 1.0 came into existence after the evolution of web 2.0.

In alluding to the version-numbers that commonly designate software upgrades, the phrase "Web 2.0" hints at an improved form of the World Wide Web. Technologies such as weblogs, wikis, podcasts, RSS feeds (and other forms of many-to-many publishing), social software, and web application programming interfaces (APIs) provide enhancements over read-only websites. The idea of "Web 2.0" can also relate to a transition of some websites from isolated information silos to interlinked computing platforms that function like locally-available software in the perception of the user. Web 2.0 also includes a social element where users generate and distribute content, often with freedom to share and re-use. This can result in a rise in the economic value of the web to businesses, as users can perform more activities online.

2.0 WEB 2.0

Web 2.0 is a term that is used to denote several different concepts: Web sites based on a particular set of technologies such as AJAX; Web sites which incorporate a strong social component, involving user profiles, friend links; Web sites which encourage user-generated content in the form of text, video, and photo postings along with comments, tags, and ratings; or just Web sites that have gained popularity in recent years and are subject to fevered speculations about valuations and IPO prospects. Nevertheless, these various categories have significant intersections, and so it is meaningful to talk broadly about the class of Web 2.0 sites without excessive ambiguity about which definition is being used.

Deciding whether a given site is considered Web2 or Web1 can be a difficult proposition. This is not least because sites are dynamic, rolling out new features or entire redesigns at will, without the active participation of their users. In particular, there is no explicit version number and active upgrade process as there is with a piece of software or a communication protocol, and many sites are referred to as being in “permanent beta”. Some sites are easy to classify: social networking sites such as Facebook and MySpace are often held up as prototypical examples of Web2, primarily due to their social networking aspects which include the user as a first-class object, but also due to their use of new user interface technologies (Facebook in particular). Other sites are resolutely Web1 in their approach: Craigslist, for example, emulates an email list server, and has no public user profiles, or fancy dynamic pages.

Many sites are hard to categorize strictly as Web1 or Web2. For example, Amazon.com launched in the mid-1990s and has gradually added features over time. The principal content (product description) is curated rather than user-created, but much of the value is added by reviews and ratings submitted by users. Profiles of users do exist, but social features such as friend links, although present, are not widely adopted. Each product has a wiki page associated with it, but these are little used. Other sites also contain a mixture of the old and the new.

Another heuristic to aid distinguishing Web2 and Web1 can be based on time: the term “Web 2.0” was coined around 2004, and many of the first truly Web2 sites began emerging in late 2003 and early 2004. So sites which have changed little in structure since the early 2000’s or before may safely be considered Web1 (such as IMDB). A definition of Web2 by O’Reilly in 2005 emphasizes Web2 as viewing the Web as a platform. It is fair to say that many of the ideas that are now called Web2 were seen in earlier forms in the efforts of AOL and Geocities. While AOL brought the Internet to the masses, it also emphasized the notion of contained communities within which people could interact. Geocities initially operated with an enforced metaphor of ‘neighborhoods’. These are precursors of current notions of groups and communities finding new and larger audiences in Web2. However, most Web2 sites differ by more forcefully making the user a first class object in their systems, and by employing new technology to make interaction easier for the user.

Some of the important site features that mark out a Web2 site include the following:

• Users as first class entities in the system, with prominent profile pages, including such features as: age, sex, location, testimonials, or comments about the user by other users.

• The ability to form connections between users, via links to other users who are “friends”, membership in “groups” of various kinds, and subscriptions or RSS feeds of “updates” from other users

• The ability to post content in many forms: photos, videos, blogs, comments and ratings on other users’ content, tagging of own or others’ content, and some ability to control privacy and sharing.

• Other more technical features, including a public API to allow third-party enhancements and “mash-ups”, and embedding of various rich content types, and communication with other users through internal email or IM systems.

Some additional explanation is required. Testimonials are comments from other users posted directly on a user’s profile. These can be general approbation (as in Flickr), or more for chatting in public (Facebook’s “wall”). These are common in Web2 but missing in the less user-centric Web1. Other data can often be added on the user’s profile page: in Web2 this is information such as job, favorite music, education etc., whereas in Web1 this is more often contact details (email addresses). Our category of subscriptions means the ability to “subscribe” to a feed of news or updates from select other users; this is handled internally, in contrast to RSS feeds which are publicly visible. Some sites offer many RSS feeds, per-user/group, whereas others like Slashdot only have feeds for a handful of broad categories. In contrast to this public sharing of information, ‘Friends only’ means that ability to make some or all information visible only to “friend” users. One can quickly verify that a site such as Facebook provides many of the above features, whereas Craigslist provides few, with many being inapplicable.

On the technical side, some of the common presentation technologies associated with Web2 sites include AJAX (autonomous JavaScript and XML), in particular use of XML Http Request to dynamically update a page without explicit reload actions; embedded flash objects e.g. to play music or videos without additional browser plug-ins.

2.1 ANALYSIS OF POPULAR SITES

A set of examples are analyzed in Table 1, based on the above list of site features. The first five listed (Facebook, YouTube, Flickr, LiveJournal and MySpace) are Web 2.0 sites, while Slashdot and Craigslist are Web 1.0. Amazon, Digg, Ebay and Friendster fall in between.

These assignments are debatable: Friendster seems to have many of the ‘social’ features in common with Facebook, but we consider it ‘Web 1.5’ since it fails to offer sufficient ways for users to interact with the content. Although much touted, features such as the ability to collaboratively edit content (i.e. Wikis) are insignificant amongst the sites considered here. The notion of “tagging” is widely discussed, but only Flickr and, to a lesser degree, Facebook and Amazon, support tagging of other people’s content; in other cases, tagging is limited to the content creator assigning tags to their content. Assigning ratings to content, or seeing statistics such as number of views is also far from ubiquitous. “Social” features, such as identifying friends, are integral to many of the Web2 sites. These are present on other sites, but less prevalent: Amazon does have friends, but this feature seems little used; Slashdot also has friends, primarily to adjust the importance of comments submitted by friends. These sites are quite functional if no friends are listed. In contrast, Facebook requires the user to add friends in order to to access most of its functionality. Figure 1 showing a page of Facebook

Figure1: A page of Facebook

3.0 WEB 2.0 APPLICATION ARCHITECTURE

Web 2.0 introduces Web developers to a range of newer approaches in application development. These include new technologies, new architectures and new toolkits for creating Web applications. For example, Flash and Flex allow developers to create rich internet applications that use the Flash Player. The Ajax approach allows Web applications to load data in the background while the user carries out other tasks.

Web 2.0 applications, take advantage of technologies that don’t require the full refresh of a page each time new data is requested. Instead, a page can be broken down into smaller components, widgets or sections. Events that occur within these component parts can trigger the loading of new data WITHOUT a full page refresh. Only the part of the interface displaying the changed data is reloaded. The fixed portions of the interface stay put.

The following diagram shows the different approach taken in Web 2.0 applications.

In a Web 2.0 approach, we still use the basic components of a Web application – we have a page, form fields and a submit button. However, it’s there that the similarity ends. In this approach, there is no need to reload the page after requesting username information.

After the username has been entered, the blur event (leaving the username form field) can trigger the validation of the entry. The first level of validation can check that the username meets requirements, for example, that it is of a minimum length. If the entry isn’t valid, a message can be displayed in a small part of the interface, such as a

element. The application can also disable the submit button to prevent the page from being accidentally submitted to the server.

If the entry is valid, JavaScript can then request information from the server about whether this username is available in the database. This request can occur asynchronously, as the user is entering their password. The application can display a message indicating that the username is being checked and can also disable the submit button while this process occurs.

If the username is available, a success message can be displayed in a

element and the submit button can be enabled. Otherwise, the user can see an error message in the

element and the submit button can be disabled. The following diagram shows this approach.

In the Web 2.0 approach, we can see that we've used:

• Small server-side tasks such as checking usernames

• Client-side events to trigger actions e.g. leaving a form field

• Asynchronous requests to the server i.e., they occur in the background and don’t stop processing

• Updates to small parts of the interface e.g., a

element

• Enabling and disabling the interface in response to user and server events

Web 2.0 applications, however, separate the data from the presentation layer in much the same way as XHTML and CSS. In Web 2.0 applications, the Web server delivers the interface once. The browser can request new or updated information from the server and then manipulate or redraw the interface as required using client-side scripting, usually JavaScript.

One of the big advantages of the Web 2.0 architecture is that developers can build applications that are responsive to the user and their actions. The user doesn’t have to wait for a server response each time they take an action on the page. There is no more “stop-start” when working on the Web.

An advantage for developers is that the popularity of this approach has seen an increase in the number of tools available for creating Web 2.0 applications. There has also been an explosion in components and widgets that provide great functionality to the user.

Adobe recently released the Flex Builder framework to assist developers of SWF applications in much the same way the Visual Studio .NET assists .NET developers. The framework provides an excellent drag and drop environment for creating interfaces as well as shipping with some advanced components for use in Web 2.0 applications.

In addition, there are large numbers of JavaScript libraries and toolkits, including those that link with server-side languages and those that create user interface widgets.

4.0 WEB 2.0 T ECHNOLOGIES AND SERVICES

Web 2.0 is an umbrella term encompassing several new Web technologies

4.1 BLOGS

A blog, short for Web log, is a powerful two-way Web based communication tool. A blog is a Web site where people can enter their thoughts, ideas, suggestions, and comments. Blog entries, also known as blog posts, are made in journal style and are usually displayed in reverse chronological order. A blog entry might contain text, images, or links to other blogs and Web pages, as well as to other media related to its topic. Most blogs are primarily textual, but some focus on photographs (photoblog or photolog), videos (videoblog or vlog), or audio (podcast). A blog written from a mobile device such as a pocket PC, mobile phone, or PDA is called an mblog, and real-time blogging is known as liveblogging. A blog can be private (internal to an organization) or public (open to anyone).

Blog entries typically consist of a title, body, permalink (permanent link), post date, comments, category or tag, trackback (the ability to notify another blog that you added a post to your blog that’s related to a post or comment on its blog), or pingback (the ability to request notification when somebody links to one of your posts). A blog is shown in figure 1.

The blogospere (or blogsphere) encompasses all blogs as a community or social network. Many blogs are interconnected, some more densely than others, as bloggers who read other blog entries link to them and reference them in their own blogs. Bloggers also post comments on each other’s blog entries. A blogroll is a blogger’s list of links to other blogs or Web sites that he or she reads.

Blogs have several unique characteristics that together distinguish them from other forms of electronic communications such as email, instant messaging, short message service, and multimedia message service. For example, anyone can publish a blog post easily and cheaply through a Web interface, and any reader can place a comment on a blog post. These blog posts and comments are instantly available on the Web.

In addition, blogs are easy to find. We can search for Blog posts by various criteria, including subject and author,using blog search engines such as Technorati (http://www.technorati.com) and Feedster (http://www.feedster.com). Some of these search engines can track the interconnections between bloggers and rank blogs depending on how many sites link to them.

Figure2: A Blog

Another unique characteristic of blogs is that a blog post can link to other blog posts, so interesting posts travel from site to site. And, through these linked blogs, people with similar interests can build relationships and form communities.

Finally, blog readers can syndicate blogs, so if you subscribe to a blog, you’ll know when it’s updated, saving you search time. You can subscribe to several blogs, and you can get free “home delivery” of blog entries to your personalized Web page or email software. Many businesses use blogs to connect and engage with customers, employees, and the general public. Each day, users create 100,000 new blogs and make 1.3 million entries.

4.2 REALLY SIMPLE SYNDICATION

RSS is a family of Web feed formats used for syndicating content from blogs or Web pages. RSS is an XML file that summarizes information items and links to the information sources. It informs users of updates to blogs or Websites they’re interested in. Web or blog RSS feeds are typically linked with the word “subscribe,” an orange rectangle, or with the letters XML or RSS in an orange box as shown in the figure 2.

Figure3: RSS in an orange box.

Feed reader or aggregator programs can check a list of feeds on the user’s behalf and display any updated articles they find. Popular Web browsers have built-in feed readers or aggregators, and you can easily add feeds to your Web page.

Atom is another syndication specification aimed at resolving issues of multiple incompatible RSS versions.

4.3 WIKIS

A wiki is a simple yet powerful Web-based collaborative-authoring (or content-management) system for creating and editing content. It lets anyone add a new article or revise an existing article through a Web browser. Users can also track changes made to an article. The term wiki is derived from the Hawaiian word wikiwiki, which means

fast or quick. The user-generated online encyclopedia Wikipedia is a wiki. Figure 2 shows the page of Wikipedia.

Wiki features include:

• A wiki markup language.

“Wikitext” provides a shorthand way of formatting text and linking external documents and contents.

• Simple site structure and navigation.

Contributors can create new pages and easily link one page to another. Because a blog site’s hierarchy and structure is flat, the navigation is simple.

• Simple templating.

When a page of wikitext is requested, wiki software converts the wiki markup to HTML and creates links between pages, and wraps this converted content in a template to provide a consistent look to all pages in the wiki.

• Support for multiple users.

Hyperlinks to pages within the wiki are created automatically.Wiki software makes links based on the page’s title, so the author doesn’t need to use, remember, or type long URLs to link one page to another within a wiki.

• Simple workflow.

We can write or edit and publish without editorial oversight or approval. Content in a wiki is managed through change monitoring and the wiki’s ability to roll back to a previous version and prevent spam. We can also control user access and privileges, if

required.

• A built-in search feature.

We can search for specific information or topic within a wiki using associated keywords. To experience a wiki, visit Wikipedia and write a new article or update an existing article, or use Wikipedia’s sandbox.

To experience a wiki, visit Wikipedia and write a new article or update an existing article, or use Wikipedia’s sandbox.

Wikis offer:

• Asynchronous contribution by a group of people—for example, experts, peers, employees, and users—who might be at different geographical locations;

• Excellent means to annotate information or discuss evolving issues;

• Higher communication efficiency and productivity compared to “back-and-forth” exchanges of emails;

• Support for harnessing the power of diverse individuals to create collaborative works;

• Centralized, shared repositories of knowledge and documents for all aspects of a project—planning, development, implementation, maintenance, and management; and

• Support for the content to evolve, expand, and improve incrementally over time.

Figure 4: Page in Wikipedia

However, wikis have some limitations that need to be addressed, as required, before they can be widely deployed. They include content accuracy, balance, comprehensiveness, consistency, and reliability; issues of legal liability, privacy, reputation, and security; and accountabilityand controllability.

4.4 MASHUPS

A Web mashup is a Web page or Web site that combines information and services from multiple sources on the Web. Similar to music mashups, where artists combine, for example, vocals from one song with the music from another, Web mashups combine information and/or complementary functionality from multiple Web sites or Web applications. A Web mashup server lets you connect, collect, and mash up anything on the Web as well as data on some backend systems.

Mashups can be grouped into seven categories: mapping, search, mobile, messaging, sports, shopping, and movies. More than 40 percent of mashups are mapping mashups. HousingMaps is a typical mashup application. It pulls sales and rental information from the classified advertisement Web site Craigslist and displays the listings on interactive maps pulled from Google Maps. Users can drag the map to see what is available for sale or rent in a given region. Several other new-breed Web applications similarly integrate multiple services under a rich user interface. For instance, Fishing Solutions uses Google Maps and information from anglers to help users find fish. Roadwatch shows all the speed cameras in an area or on route to a destination.

It’s easier and quicker to create a mashup than to code an application from scratch in a traditional way. This capability is one of Web 2.0’s most important and valuable features.

Mashup API.

Mashups are generally created using application programming interfaces. Simple and well-documented APIs make mashup creation easy. An API is an interface provided by an application that lets users interact with or respond to data or service requests from another program, other applications, or Websites. APIs facilitate data exchange between applications, allow the creation of new applications, and form the foundation for the “Web as a platform” concept.

For example, Google Maps’ API lets developers integrateGoogle Maps into their Web sites using their own data points.APIs for other services, such as weather or calendar information and search functions, are also available. Amazon’s Web site offers several APIs, making it easy for other business Web sites to interact with it.For a directory of categories of APIs available for use.

In addition to APIs, we can incorporate data feeds into a mashup.Or, at the most basic level, programmers can use screen scraping, a technique for extracting any information, of any type, from any Web page.

The power of mashups.

A mashup’s value isn’t in the data or service itself, but in a better user interface for the data, or in its ability to combine data from several sources in interesting or significant ways. Three main types of mashups are in use; those that provide the following:

• An enhanced user interface.

Drawing on data from mostly one source, this type of mashup provides a better

interface—for example, a better way to navigate through information, a more responsive interface, or the presentation of more relevant information by displaying only a subset of information that is of particular interest to the user.

• Value-added information by aggregation.

By bringing together information from various sources on the Web—both internal and external to an enterprise—into a dashboard-like view, this type of mashup adds value by aggregating the data, making the combined

data more relevant.

• Value-added information augmented with an enhanced user interface.

This type of mashup aggregates data from different sources and presents the data with a better user interface.

Developers and enterprises are beginning to use mashups to create new Web applications that provide value-added new features, knit together multiple services, and provide rich user interfaces. Because they are easy to create, even employees who are technically less-savvy can create Web mashups, rather than having to rely on enterprise IT teams.

An enterprise can use mashups internally to collect information from different sources and combine it in intelligent ways to help people make smarter decisions. For example, executives can use mashups to gain a deeper understanding of customers and sales, and thus to make better decisions. Mashups also find application in areas such as payroll, customer relationship management, logistics, procurement, marketing, and e-commerce.

By opening up data and services that mashup creators can use, enterprises can gain strategic advantages. For example, the mashed-up applications can divert new users to their sites, or mashup creators could develop a new Web site that provides better interfaces to an enterprise’s existing Web site, which in turn could bring more visitors to the enterprise’s site.

Although a mashup makes it easy to draw on multiple data sources or services to create new applications quickly, there are also risks in using someone’s mashup service or API, in terms of their continued support, reliability, security, and scalability. Developers and enterprises that deploy and use mashup applications should be aware of the risks and limitations and choose dependable services.

4.5 TAGS, FOLKSONOMY AND TAG CLOUDS

Tags are keywords added to articles in blogs or Web pages via social page tag tools such as del.icio.us (http://del.icio.us), Technorati, and Yahoo’s My Web. Most blogs and Web publications use tags. Tags are also known as labels, and the process of creating tags is known as tagging.

Folksonomy refers to user-created taxonomies of information. It is an ad hoc classification scheme that Web users create as they surf the Web to categorize the content they find online. It uses collaboratively generated,open-ended tags or labels that categorize content such as Web pages, online photographs, and Web links. A special feature of folksonomies is that they don’t have a hierarchy as in professionally developed taxonomies with controlled vocabularies, and hence they’re inherently open ended.

Folksonomies (such as user-created tags for photos on Flickr and tags for bookmarking in Del.icio.us) can, therefore, respond quickly to changes, innovations, and fads in how users categorize content on the Web.

Social bookmarking is the process by which users bookmark interesting pages and assign tags to each. Users can then share their tagged bookmarks (see, for example,

del.icio.us). Social bookmarking is a great way of capturing contextual knowledge.

A tag cloud is a visual depiction of a list of content tags used on a Web site or blog, with some kind of visualization for each tag’s popularity level. Generally, more frequently used tags are depicted in a larger font or are emphasized some other way, and the display order is alphabetical, making it easy to find a tag by popularity or place in the alphabet. Selecting a tag within a tag cloud will generally give you a collection of items associated with that tag. We can add a tag cloud to your Web site or blog using free, online services provided by vendors such as ZoomClouds, or create a tag cloud yourself. Popular Web sites such as Flickr, del.icio.us, and Digg use tagging and social bookmarking services.

We can use tags and tag clouds to derive inferences from an unstructured data source.

Figure5: A tag cloud presenting Web 2.0 themes.

5.0 DEVELOPMENT APPROACHES

Developers use three principle development approaches to create Web 2.0 applications: Asynchronous JavaScript and XML (AJAX), Flex, and the Google Web Toolkit.

5.1 AJAX

AJAX is a relatively new approach to creating Web applications. It enriches the user interface, making it highly interactive and more responsive. It’s really several technologies coming together in powerful new ways—XHTML or HTML, cascading stylesheets (CSS), JavaScript, and XML.

AJAX-style programming makes Web pages more responsive by exchanging small amounts of data with the server so that the entire Web page doesn’t have to be reloaded each time the user requests a change. An AJAX application eliminates the start-stop-start-stop nature of Web interaction by introducing an intermediary—an AJAX engine—between the user and the server. The AJAX engine both renders the user interface and communicates with the server on the user’s behalf. It thus overcomes the page-loading requirements of HTML/HTTP mediated Web pages and so significantly improves a Web page’s interactivity, speed, and usability, making it easier to deploy rich-client Web applications.

5.2 FLEX

Adobe Flex is an application development solution for creating and delivering cross-platform rich Internet applications (RIAs) on the Web. Flex is based on Flash and provides a standards-based language and programming model that supports common design patterns.It provides a more productive Eclipse-based development environment; dramatically improves application performance; supports new classes of applications,such as those requiring real-time data push; and provides more fine-grained control over an application’s look and feel.Flex and Flash have complementary strengths.While Flash helps users create rich interactive content, Flex leverages the development of data-driven RIAs.

Flex lets enterprises create engaging, interactive, expressive, scalable applications that dramatically enhance the user experience by increasing user interactivity with the application. For example, a data visualization application built in Flex can pull data from multiple backend sources and display it visually. A product configuration application can help customers navigate the process of selecting or customizing products online.

5.3 GOOGLE WEB TOOLKIT

Google Web Toolkit is an open source Java development framework that makes it easy to develop and debug AJAX applications. Writing dynamic Web applications is a tedious and error-prone process, and JavaScript’s lack of modularity makes sharing, testing, and reusing AJAX components difficult and fragile.

GWT lets developers create applications in Java using the Java development tools of their choice. Its compiler translates the Java application to browser-compliant JavaScript and HTML for deployment. The toolkit also provides widgets to construct the user interface elements comprising an AJAX application. So, GWT overcomes the limitations of writing AJAX applications using a mix of technologies, while offering users the same dynamic, standards-compliant experience.

6.0 WEB 2.0 DEVELOPMENT TOOLS

Several development tools are available for creating blogs, wikis, mashups, and social networks. These tools make adoption of Web 2.0 easier, quicker, and cheaper.

6.1 BLOG SOFTWARE

Blog software, also called blogware, is designed for creating and managing blogs. The following are three popular blog software programs:

Movable Type is a proprietary blog publishing system that must be installed on a user’s Web server. It supports most blogging features, including user accounts, comments, categories, themes, and trackbacks, and is extensible through a large library of third-party plug-ins. The system is written in Perl and stores the blog’s content and associated data within MySQL.

WordPress is a blog hosting provider. The online system lets users create and manage their own blogs without requiring technical knowledge. To set up a blog, a user registers with WordPress and opens a free hosting account. Users don’t need to register to read or comment on blogs hosted on the site, unless the blog owner requires it. Most of the site’s features are free, but some, such as a CSS editor and domain mapping, are available only to users whopay for them.

Blogger is another blog hosting system. Blogger can host blogs internally (using a blogspot.com address), externally on a user’s domain, or on the user’s server (through FTP or SFTP). Blogger also supports Google’s AdSense service as a simple way of generating revenue from running a blog.

6.2WIKI ENGINES

Wiki software or a wiki engine runs a wiki system. A wiki engine is usually implemented as server-side script that runs on one or more Web servers, with the content generally stored in a relational database management system. MediaWiki and TWiki are two of the more sophisticated open source wiki applications. Commercial wikiengines include Socialtext( http://www.socialtext.com), JotSpot(http://www.jotspot.com), and Atlassia (http://.www.atlassian.com). Other popular Wiki engines include MoinMoin (http://moinmoin.wikiwikiWeb.de), PmWiki (http://www.pmwiki.org), and UseModWiki

(http://www.usemod.com/cgi-bin/wiki.pl).

Choosing a wiki engine for an application depends on several factors, including the following:

• Editor features—WYSIWYG capabilities, sectional editing, rollback to earlier versions, file upload, image insertion, and so on

• Reader features—table of contents, navigation bar, search, access/usage statistics, article rating, and printable version

• Groupware features—forum, gallery, and message system

• User management—user personal page and personalized toolbar and preferences

• Access controls—user access and privilege controls (important for internal enterprise applications)

• Content import and export—the ability to import content from external files (for example, HTML or a Word document) or to export wiki content in a specified file format

• Extensibility—availability of third-party plug-ins and provisions for creating them, if required

• Portability—support for other formats, so you can export your text to other systems

• Scalability—number of articles, volume of content, and number of users (writers/readers) the wiki can handle

• Hosting platform—where the wiki will be hosted (on a server or a local machine) and whether it will require online access.

6.3 MASHUP TOOLS

Several mashup tools are available for creating Web mashups. These include the following:

• Above All Studio, http://www.aboveallsoftware.com/product_studio.asp

• ActionBridge, http://www.nimaya.com/salesforce/index.asp

• Dapper, http://www.dappit.com

• DataMashups, http://DataMashups.com

• JackBuilder, http://jackbe.com/Products/ide.php

• Process Engine, http://www.procession.com/products /process_engine.html

• Ratchet-X Studio, http://www.ratchetsoft.com/sitenonie/html/studio.html

• RSSBus, http://rssbus.com

Many more mashup tools will be commercially available .You can experience the elegance and simplicity of mashups by assembling one yourself at DataMashups, which provides an online service preview that lets you start assembling mashups using a rich palette of preexisting widgets, feeds, data from local and remote SQL databases, and more.

7.0 CONCLUSION

Although Web 2.0 began simply as a consumer phenomenon, attracting numerous users and contributors for social applications such as MySpace, Flickr and YouTube, and the online encyclopedia Wikipedia, it has significantly impacted many other application areas by enabling better, faster, and richer applications, while reducing costs of development and deployment and offering tangible benefits. For example, Web 2.0 can help businesses in product development, market research, competitive intelligence gathering, and revenue generation. In addition to the wide array of Web 2.0 applications under development, a growing number of companies are offering innovative new services free online.

Web 2.0 applications, however, pose a new design and development dilemma: fast and easy versus well designed and well-engineered. We need to rethink Web application

development methods in light of Web 2.0. Addressing the issues of scalability, performance, and security of Web 2.0 applications is another challenge for IT professionals.

8.0 FUTURE WORK

Web 3.0: It seems we have everything whatever we had wished for in Web 2.0, but it is way behind when it comes to intelligence. Perhaps a six year old child has a better analytical abilities than the existing search technologies! Keyword based search of web 2.0 resulted in an information overload. The following attributes are going to be a part of Web 3.0:

• contextual Search
• Tailor made Search
• Personalized Search
• Evolution of 3D Web
• Deductive Reasoning

Though Web is yet to see something which can be termed as fairly intelligent but the efforts to achieve this goal has already began. 2 weeks back the Official Google Blog mentioned about how Google search algorithm is now getting intelligent as it can identify many synonyms.

For example Pictures & Photos are now treated as similar in meaning. From now onwards your search query GM crop will not lead you to GM (General Motors) website. Why? Cause, first by synonym identification Google will understand that GM may mean General Motors or Genetically Modified. Then by context i.e. by the keyword crop it will deduce that the user wants information on genetically modified crops and not on General Motors. Similarly, GM car will not lead you to genetically modified crop. Try out yourself to check how this newly added artificial intelligence works in Google. Also, there are many websites built on Web 3.0 which personalizes your search. The web is indeed getting intelligent.