INTRODUCTION Web 2.0 is a loosely defined intersection of web application features that facilitate participatory information sharing, interoperability, user-centered design, and collaboration on the World Wide Web. A Web 2.0 site allows users to interact and collaborate with each other in a social media dialogue as creators (prosumers) of user-generated content in a virtual community, in contrast to websites where users (consumers) are limited to the passive viewing of content that was created for them. Examples of Web 2.0 include social networking sites, blogs, wikis, video sharing sites, hosted services, web applications, mashups and folksonomies.
The term is closely associated with Tim OReilly because of the OReilly Media Web 2.0 conference in late 2004. Although the term suggests a new version of the World Wide Web, it does not refer to an update to any technical specification, but rather to cumulative changes in the ways software developers and end-users use the Web. Whether Web 2.0 is qualitatively different from prior web technologies has been challenged by World Wide Web inventor Tim Berners-Lee, who called the term a "piece of jargon", precisely because he intended the Web in his vision as "a collaborative medium, a place where we [could] all meet and read and write". He called it the "Read/Write Web".
CHARACTERISTICS The Web 2.0 offers all users the same freedom to contribute. While this opens the possibility for rational debate and collaboration, it also opens the possibility for "spamming" and "trolling" by less rational users. The impossibility of excluding group members who don’t contribute to the provision of goods from sharing profits gives rise to the possibility that rational members will prefer to withhold their contribution of effort and free ride on the contribution of others. This requires what is sometimes called radical trust by the management of the website. According to Best, the characteristics of Web 2.0 are: rich user experience, user participation, dynamic content, metadata, web standards and scalability. Further characteristics, such as openness, freedom and collective intelligence by way of user participation, can also be viewed as essential attributes of Web 2.0.
CONCEPTS Web 2.0 can be described in 3 parts, which are as follows: Rich Internet application (RIA) — defines the experience brought from desktop to browser whether it is from a graphical point of view or usability point of view. Some buzzwords related to RIA are Ajax and Flash. Web-oriented architecture (WOA) — is a key piece in Web 2.0, which defines how Web 2.0 applications expose their functionality so that other applications can leverage and integrate the functionality providing a set of much richer applications (Examples are: Feeds, RSS, Web Services, Mash-ups) Social Web — defines how Web 2.0 tends to interact much more with the end user and make the end-user an integral part. As such, Web 2.0 draws together the capabilities of client- and server-side software, content syndication and the use of network protocols. Standards-oriented web browsersmay use plug-ins and software extensions to handle the content and the user interactions. Web 2.0 sites provide users with information storage, creation, and dissemination capabilities that were not possible in the environment now known as "Web 1.0".
MARKETING For marketers, Web 2.0 offers an opportunity to engage consumers. A growing number of marketers are using Web 2.0 tools to collaborate with consumers on product development, service enhancement and promotion. Companies can use Web 2.0 tools to improve collaboration with both its business partners and consumers. Among other things, company employees have created wikis—Web sites that allow users to add, delete, and edit content — to list answers to frequently asked questions about each product, and consumers have added significant contributions. Another marketing Web 2.0 lure is to make sure consumers can use the online community to network among themselves on topics of their own choosing.
WEB 2.0 IN EDUCATION Web 2.0 technologies provide teachers with new ways to engage students in a meaningful way. "Children raised on new media technologies are less patient with filling out worksheets and listening to lectures" because students already participate on a global level. The lack of participation in a traditional classroom stems more from the fact that students receive better feedback online. Traditional classrooms have students do assignments and when they are completed, they are just that, finished. However, Web 2.0 shows students that education is a constantly evolving entity. Whether it is participating in a class discussion, or participating in a forum discussion, the technologies available to students in a Web 2.0 classroom does increase the amount they participate.
DISTRIBUTION OF MEDIA XML and RSS Many regard syndication of site content as a Web 2.0 feature. Syndication uses standardized protocols to permit end-users to make use of a sites data in another context (such as another website, a browser plugin, or a separate desktop application). Protocols permitting syndication include RSS (really simple syndication, also known as web syndication), RDF (as in RSS 1.1), and Atom, all of them XML-based formats. Observers have started to refer to these technologies as web feeds. Specialized protocols such as FOAF and XFN (both for social networking) extend the functionality of sites or permit end-users to interact without centralized websites.
Web APIs Web 2.0 often uses machine-based interactions such as REST and SOAP. Servers often expose proprietary Application programming interfaces (API), but standard APIs (for example, for posting to a blog or notifying a blog update) have also come into use. Most communications through APIs involve XML or JSON payloads. REST APIs, through their use of self-descriptive messages and hypermedia as the engine of application state, should be self-describing once an entry URI is known. Web Services Description Language (WSDL) is the standard way of publishing a SOAP API and there are a range of web service specifications. EMML, or Enterprise Mashup Markup Language by the Open Mashup Alliance, is an XML markup language for creating enterprise mashups.
CRITICISM Critics of the term claim that "Web 2.0" does not represent a new version of the World Wide Web at all, but merely continues to use so-called "Web 1.0" technologies and concepts. First, techniques such as AJAX do not replace underlying protocols like HTTP, but add an additional layer of abstraction on top of them. Second, many of the ideas of Web 2.0 had already been featured in implementations on networked systems well before the term "Web 2.0" emerged. Amazon.com, for instance, has allowed users to write reviews and consumer guides since its launch in 1995, in a form of self- publishing. Amazon also opened its API to outside developers in 2002. Previous developments also came from research in computer- supported collaborative learning and computer supported cooperative work (CSCW) and from established products likeLotus Notes and Lotus Domino, all phenomena that preceded Web 2.0.