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Web 2.0 describes World Wide Web sites that use technology beyond the static pages of earlier Web sites. The term was coined in 1999 by Darcy DiNucci and was popularized by Tim O'Reilly at the O'Reilly Media Web 2.0 conference in late 2004. Although Web 2.0 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 way Web pages are made and used.
A Web 2.0 site may allow users to interact and collaborate with each other in a social media dialogue as creators of user-generated content in a virtual community, in contrast to Web sites where people are limited to the passive viewing of content. Examples of Web 2.0 include social networking sites, blogs, wikis, folksonomies, video sharing sites, hosted services, Web applications, and mashups.
Whether Web 2.0 is substantively different from prior Web technologies has been challenged by World Wide Web inventor Sir Tim Berners-Lee, who describes the term as jargon. His original vision of the Web was "a collaborative medium, a place where we [could] all meet and read and write".
According to Cormode, G. and Krishnamurthy, B. (2008): "content creators were few in Web 1.0 with the vast majority of users simply acting as consumers of content." 
Personal web pages were common, consisting mainly of static pages hosted on ISP-run servers, or on free hosting services such as Geocities. With the advent of Web 2.0, it was more common for the average web user to have social networking profiles on sites such as Myspace and Facebook, as well as personal blogs on one of the new low-cost web hosting services. The content for both were generated dynamically from content stored in a relational database, allowing for readers to comment directly on pages in a way that was not previously common.
Web 2.0 capabilities were present in the days of Web 1.0 but implemented differently. For example, a Web 1.0 site may have had a guestbook page to publish visitor comments, instead of a comment section at the end of each page. Server performance and bandwidth considerations meant that having a long comments thread on each page could potentially slow down the site.
Terry Flew, in his 3rd Edition of New Media described what he believed to characterize the differences between Web 1.0 and Web 2.0:
"move from personal websites to blogs and blog site aggregation, from publishing to participation, from web content as the outcome of large up-front investment to an ongoing and interactive process, and from content management systems to links based on tagging (folksonomy)".
Flew believed it to be the above factors that form the basic change in trends that resulted in the onset of the Web 2.0 "craze".
Some design elements of a Web 1.0 site include:
The Web we know now, which loads into a browser window in essentially static screenfuls, is only an embryo of the Web to come. The first glimmerings of Web 2.0 are beginning to appear, and we are just starting to see how that embryo might develop. The Web will be understood not as screenfuls of text and graphics but as a transport mechanism, the ether through which interactivity happens. It will [...] appear on your computer screen, [...] on your TV set [...] your car dashboard [...] your cell phone [...] hand-held game machines [...] maybe even your microwave oven.
Writing when Palm Inc. was introducing its first Web-capable personal digital assistant, supporting Web access with WAP, DiNucci saw the Web "fragmenting" into a future that extended far beyond the browser/PC combination it was identified with. Her vision of the Web's future focused on how the basic information structure and hyperlinking mechanism introduced by HTTP would be used by a variety of devices and platforms. As such, her use of the "2.0" designation refers to a next version of the Web that does not directly relate to the term's current use.
The term Web 2.0 did not resurface until 2002. These authors focus on the concepts currently associated with the term where, as Scott Dietzen puts it, "the Web becomes a universal, standards-based integration platform". John Robb wrote: "What is Web 2.0? It is a system that breaks with the old model of centralized Web sites and moves the power of the Web/Internet to the desktop."
In 2004, the term began its rise in popularity when O'Reilly Media and MediaLive hosted the first Web 2.0 conference. In their opening remarks, John Battelle and Tim O'Reilly outlined their definition of the "Web as Platform", where software applications are built upon the Web as opposed to upon the desktop. The unique aspect of this migration, they argued, is that "customers are building your business for you". They argued that the activities of users generating content (in the form of ideas, text, videos, or pictures) could be "harnessed" to create value. O'Reilly and Battelle contrasted Web 2.0 with what they called "Web 1.0". They associated this term with the business models of Netscape and the Encyclopædia Britannica Online. For example,
Netscape framed "the web as platform" in terms of the old software paradigm: their flagship product was the web browser, a desktop application, and their strategy was to use their dominance in the browser market to establish a market for high-priced server products. Control over standards for displaying content and applications in the browser would, in theory, give Netscape the kind of market power enjoyed by Microsoft in the PC market. Much like the "horseless carriage" framed the automobile as an extension of the familiar, Netscape promoted a "webtop" to replace the desktop, and planned to populate that webtop with information updates and applets pushed to the webtop by information providers who would purchase Netscape servers.
In short, Netscape focused on creating software, updating it on occasion, and distributing it to the end users. O'Reilly contrasted this with Google, a company that did not at the time focus on producing software, such as a browser, but instead on providing a service based on data such as the links Web page authors make between sites. Google exploits this user-generated content to offer Web search based on reputation through its "PageRank" algorithm. Unlike software, which undergoes scheduled releases, such services are constantly updated, a process called "the perpetual beta". A similar difference can be seen between the Encyclopædia Britannica Online and Wikipedia: while the Britannica relies upon experts to create articles and releases them periodically in publications, Wikipedia relies on trust in (sometimes anonymous) community members to constantly and quickly build content. Wikipedia is not based on expertise but rather an adaptation of the open source software adage "given enough eyeballs, all bugs are shallow", and it produces and updates articles constantly. O'Reilly's Web 2.0 conferences have been held every year since 2004, attracting entrepreneurs, large companies, and technology reporters.
The term Web 2.0 was initially championed by bloggers and by technology journalists, culminating in the 2006 TIME magazine Person of The Year (You). That is, TIME selected the masses of users who were participating in content creation on social networks, blogs, wikis, and media sharing sites. In the cover story, Lev Grossman explains:
It's a story about community and collaboration on a scale never seen before. It's about the cosmic compendium of knowledge Wikipedia and the million-channel people's network YouTube and the online metropolis MySpace. It's about the many wresting power from the few and helping one another for nothing and how that will not only change the world but also change the way the world changes.
Web 2.0 sites allow users to do more than just retrieve information. Instead of merely reading, a user is invited to comment on published articles, or create a user account or profile on the site, which may enable increased participation. By increasing emphasis on these already-extant capabilities, they encourage the user to rely more on their browser for user interface, application software and file storage facilities. This has been called "network as platform" computing. Major features of Web 2.0 include social networking sites, user created Web sites, self-publishing platforms, tagging, and social bookmarking. Users can provide the data that is on a Web 2.0 site and exercise some 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. Some scholars have put forth cloud computing as an example of Web 2.0 because cloud computing is simply an implication of computing on the Internet.
Web 2.0 offers all users the same freedom to contribute. While this opens the possibility for serious debate and collaboration, it also increases the incidence of "spamming" and "trolling" by unscrupulous or misanthropic 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 serious 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 Web site. 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.
The key features of Web 2.0  include:
To allow users to continue to interact with the page, communications such as data requests going to the server are separated from data coming back to the page (asynchronously). Otherwise, the user would have to routinely wait for the data to come back before they can do anything else on that page, just as a user has to wait for a page to complete the reload. This also increases overall performance of the site, as the sending of requests can complete quicker independent of blocking and queueing required to send data back to the client.
On the server-side, Web 2.0 uses many of the same technologies as Web 1.0. Languages such as PHP, Ruby, Perl, Python, as well as Enterprise Java (J2EE) and Microsoft.NET Framework, are used by developers to output data dynamically using information from files and databases. What has begun to change in Web 2.0 is the way this data is formatted. In the early days of the Internet, there was little need for different Web sites to communicate with each other and share data. In the new "participatory Web", however, sharing data between sites has become an essential capability. To share its data with other sites, a Web site must be able to generate output in machine readable formats such as XML (Atom, RSS, etc.) and JSON. When a site's data is available in one of these formats, another Web site can use it to integrate a portion of that site's functionality into itself.
Web 2.0 can be described in three parts:
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 browsers may 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".
While SLATES forms the basic framework of Enterprise 2.0, it does not contradict all of the higher level Web 2.0 design patterns and business models. In this way, a new Web 2.0 report from O'Reilly is quite effective and diligent in interweaving the story of Web 2.0 with the specific aspects of Enterprise 2.0. It includes discussions of self-service IT, the long tail of enterprise IT demand, and many other consequences of the Web 2.0 era in the enterprise. The report also makes many sensible recommendations around starting small with pilot projects and measuring results, among a fairly long list.
A third important part of Web 2.0 is the Social web. The social Web consists of a number of online tools and platforms where people share their perspectives, opinions, thoughts and experiences. Web 2.0 applications tend to interact much more with the end user. As such, the end user is not only a user of the application but also a participant by:
The popularity of the term Web 2.0, along with the increasing use of blogs, wikis, and social networking technologies, has led many in academia and business to append a flurry of 2.0's to existing concepts and fields of study, including Library 2.0, Social Work 2.0, Enterprise 2.0, PR 2.0, Classroom 2.0, Publishing 2.0, Medicine 2.0, Telco 2.0, Travel 2.0, Government 2.0, and even Porn 2.0. Many of these 2.0s refer to Web 2.0 technologies as the source of the new version in their respective disciplines and areas. For example, in the Talis white paper "Library 2.0: The Challenge of Disruptive Innovation", Paul Miller argues
Blogs, wikis and RSS are often held up as exemplary manifestations of Web 2.0. A reader of a blog or a wiki is provided with tools to add a comment or even, in the case of the wiki, to edit the content. This is what we call the Read/Write web. Talis believes that Library 2.0 means harnessing this type of participation so that libraries can benefit from increasingly rich collaborative cataloging efforts, such as including contributions from partner libraries as well as adding rich enhancements, such as book jackets or movie files, to records from publishers and others.
Here, Miller links Web 2.0 technologies and the culture of participation that they engender to the field of library science, supporting his claim that there is now a "Library 2.0". Many of the other proponents of new 2.0s mentioned here use similar methods.
The meaning of Web 2.0 is role dependent. For example, some use Web 2.0 to establish and maintain relationships through social networks, while some marketing managers might use this promising technology to "end-run traditionally unresponsive I.T. department[s]."
There is a debate over the use of Web 2.0 technologies in mainstream education. Issues under consideration include the understanding of students' different learning modes; the conflicts between ideas entrenched in informal on-line communities and educational establishments' views on the production and authentication of 'formal' knowledge; and questions about privacy, plagiarism, shared authorship and the ownership of knowledge and information produced and/or published on line.
Mainstream media usage of Web 2.0 is increasing. Saturating media hubs—like The New York Times, PC Magazine and Business Week — with links to popular new Web sites and services, is critical to achieving the threshold for mass adoption of those services.
Web 2.0 offers financial institutions abundant opportunities to engage with customers. Networks such as Twitter, Yelp and Facebook are now becoming common elements of multichannel and customer loyalty strategies, and banks are beginning to use these sites proactively to spread their messages. In a recent article for Bank Technology News, Shane Kite describes how Citigroup's Global Transaction Services unit monitors social media outlets to address customer issues and improve products. Furthermore, the financial services industry uses Twitter to release "breaking news" and upcoming events, and YouTube to disseminate videos that feature executives speaking about market news.
Small businesses have become more competitive by using Web 2.0 marketing strategies to compete with larger companies. As new businesses grow and develop, new technology is used to decrease the gap between businesses and customers. Social networks have become more intuitive and user friendly to provide information that is easily reached by the end user. For example, companies use Twitter to offer customers coupons and discounts for products and services.
According to Google Timeline, the term Web 2.0 was discussed and indexed most frequently in 2005, 2007 and 2008. Its average use is continuously declining by 2–4% per quarter since April 2008.
|This section may be unbalanced towards certain viewpoints. (December 2011)|
Web 2.0 technologies can provide students with more engagement through greater customization and choice of topics, and less distraction from their peers.
Will Richardson stated in Blogs, Wikis, Podcasts and other Powerful Web tools for the Classrooms, 3rd Edition that, "The Web has the potential to radically change what we assume about teaching and learning, and it presents us with important questions to ponder: What needs to change about our curriculum when our students have the ability to reach audiences far beyond our classroom walls?" Web 2.0 tools are needed in the classroom to prepare both students and teachers for the shift in learning that Collins and Halverson describe. According to Collins and Halverson, the self-publishing aspects as well as the speed with which their work becomes available for consumption allows teachers to give students the control they need over their learning. This control is the preparation students will need to be successful as learning expands beyond the classroom."
By allowing students to use the technology tools of Web 2.0, teachers are giving students the opportunity to share what they learn with peers. Some are concerned that these technologies could hinder the personal interaction of students: "Social networking sites have worried many educators (and parents) because they often bring with them outcomes that are not positive: narcissism, gossip, wasted time, 'friending', hurt feelings, ruined reputations, and sometimes unsavory, even dangerous activities".
Web 2.0 calls for major shifts in the way education is provided for students. One of the biggest shifts that Will Richardson points out in his book Blogs, Wikis, Podcasts, and Other Powerful Web Tools for Classrooms is the fact that education should be collaboratively constructed. This means that students, in a Web 2.0 classroom, are expected to collaborate with their peers. By making the shift to a Web 2.0 classroom, teachers are creating a more open atmosphere where students are expected to stay engaged and participate in class discussions. In fact, there are many ways for educators to use Web 2.0 technologies in their classrooms.
"Weblogs are not built on static chunks of content. Instead they are comprised of reflections and conversations that in many cases are updated every day [...] They demand interaction." Will Richardson's observation of the essence of Weblogs speaks directly to why blogs are so well suited to discussion based classrooms. As long as the students are invested in the project, Weblogs give students a public space to interact with one another and the content of the class.
For example, Laura Rochette implemented the use of blogs in her American History class and noted that in addition to an overall improvement in quality, the use of the blogs as an assignment demonstrated synthesis level activity from her students. In her experience, asking students to conduct their learning in the digital world meant asking students "to write, upload images, and articulate the relationship between these images and the broader concepts of the course, [in turn] demonstrating that they can be thoughtful about the world around them."
The spread of participatory information-sharing over the world, combined with recent improvements in lower cost internet access in developing countries, has opened up new possibilities for peer-to-peer charities, which allow individuals to contribute small amounts to charitable projects for other individuals. Web sites such as Donors Choose and Global Giving now allow small-scale donors to direct funds to individual projects of their choice.
A popular twist on internet-based philanthropy is the use of peer-to-peer lending for charitable purposes. Sites like Kiva, KivaZip, Zidisha, MyC4, Rang De, Vittana, Lendwithcare.org offers peer-to-peer microlending platforms to link lenders and borrowers across international borders.
The social work profession is embracing Web 2.0 technologies. One of the first references to Social Work 2.0 was made in "The New Social Worker" magazine, which was started by Linda May Grobman, MSW, ACSW, LSW, in spring of 1994. This online publication continues to explore the application of Web 2.0 technology within the social work community. The first article of an ongoing SW 2.0 series was entitled "Caring Bridge: A Valuable Tool for Social Workers and Those With Critical Illness," written by Karen Zgoda, MSW, LCSW. It was followed by a column entitled, "Social Work? There's a Blog for That," by Karen Zgoda.The article noted that blogging was quickly becoming a phenomenon within the social work community. Both students and professionals had begun chronicling their career development as well as sharing information from their respective practice areas. In 2007, Jonathan Singer, Ph.D. started The Social Work Podcast, which provides information about all things social work, followed by a more formalized outline of the meaning of Social Work 2.0 in 2009.
In 2010, Social Work Today Magazine analyzed the disconnect between the social work community and the under utilization of advanced technologies in social work organizations. Meanwhile, mobile technology was changing the way society accessed the World Wide Web and communicated with each other. With the expansion of mobile technology, the National Association of Social Workers (NASW) published a 2010 study investigating child welfare workers' attitudes towards mobile technology tools. Social workers realize the potential that technology presents in expanding their ability to connect with each other and service users as reported by The Guardian in an April 7, 2011 article. As time and technology evolve, the social work profession is expanding with it.
Ajax has prompted the development of Web sites that mimic desktop applications, such as word processing, the spreadsheet, and slide-show presentation. In 2006 Google, Inc. acquired one of the best-known sites of this broad class, Writely. WYSIWYG wiki and blogging sites replicate many features of PC authoring applications.
Several browser-based services have emerged, including EyeOS and YouOS.(No longer active.) Although named operating systems, many of these services are application platforms. They mimic the user experience of desktop operating-systems, offering features and applications similar to a PC environment, and are able to run within any modern browser. However, these so-called "operating systems" do not directly control the hardware on the client's computer.
Numerous web-based application services appeared during the dot-com bubble of 1997–2001 and then vanished, having failed to gain a critical mass of customers. In 2005, WebEx acquired one of the better-known of these, Intranets.com, for $45 million.
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 site's data in another context (such as another Web site, 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 which are XML-based formats. Observers have started to refer to these technologies as Web feeds.
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 Application programming interface and there are a range of Web service specifications.
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 were already 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 like Lotus Notes and Lotus Domino, all phenomena that preceded Web 2.0.
Perhaps the most common criticism is that the term is unclear or simply a buzzword. For many people who work in software, version numbers like 2.0 and 3.0 are for software versioning or hardware versioning only, and to assign 2.0 arbitrarily to many technologies with a variety of real version numbers has no meaning. The web does not have a version number. For example, in a 2006 interview with IBM developerWorks podcast editor Scott Laningham, Tim Berners-Lee described the term "Web 2.0" as a jargon:
"Nobody really knows what it means...If Web 2.0 for you is blogs and wikis, then that is people to people. But that was what the Web was supposed to be all along... Web 2.0, for some people, it means moving some of the thinking [to the] client side, so making it more immediate, but the idea of the Web as interaction between people is really what the Web is. That was what it was designed to be... a collaborative space where people can interact."
Other critics labeled Web 2.0 "a second bubble" (referring to the Dot-com bubble of circa 1995–2001), suggesting that too many Web 2.0 companies attempt to develop the same product with a lack of business models. For example, The Economist has dubbed the mid- to late-2000s focus on Web companies as "Bubble 2.0".
In terms of Web 2.0's social impact, critics such as Andrew Keen argue that Web 2.0 has created a cult of digital narcissism and amateurism, which undermines the notion of expertise by allowing anybody, anywhere to share and place undue value upon their own opinions about any subject and post any kind of content, regardless of their actual talent, knowledge, credentials, biases or possible hidden agendas. Keen's 2007 book, Cult of the Amateur, argues that the core assumption of Web 2.0, that all opinions and user-generated content are equally valuable and relevant, is misguided. Additionally, Sunday Times reviewer John Flintoff has characterized Web 2.0 as "creating an endless digital forest of mediocrity: uninformed political commentary, unseemly home videos, embarrassingly amateurish music, unreadable poems, essays and novels... [and that Wikipedia is full of] mistakes, half truths and misunderstandings". Michael Gorman, former president of the American Library Association has been vocal about his opposition to Web 2.0 due to the lack of expertise that it outwardly claims, though he believes that there is hope for the future.
"The task before us is to extend into the digital world the virtues of authenticity, expertise, and scholarly apparatus that have evolved over the 500 years of print, virtues often absent in the manuscript age that preceded print".
There is also a growing body of critique of Web 2.0 from the perspective of political economy. Since, as Tim O'Reilly and John Batelle put it, Web 2.0 is based on the "customers... building your business for you," critics have argued that sites such as Google, Facebook, YouTube, and Twitter are exploiting the "free labor" of user-created content. Web 2.0 sites use Terms of Service agreements to claim perpetual licenses to user-generated content, and they use that content to create profiles of users to sell to marketers. This is part of increased surveillance of user activity happening within Web 2.0 sites. Jonathan Zittrain of Harvard's Berkman Center for the Internet and Society argues that such data can be used by governments who want to monitor dissident citizens.
The rise of AJAX-driven web sites where much of the content must be rendered on the client has meant that users of older hardware are given worse performance versus a site purely composed of HTML, where the processing takes place on the server. Accessibility for disabled or impaired users may also suffer in a Web 2.0 site.
In November 2004, CMP Media applied to the USPTO for a service mark on the use of the term "WEB 2.0" for live events. On the basis of this application, CMP Media sent a cease-and-desist demand to the Irish non-profit organization IT@Cork on May 24, 2006, but retracted it two days later. The "WEB 2.0" service mark registration passed final PTO Examining Attorney review on May 10, 2006, and was registered on June 27, 2006. The European Union application (which would confer unambiguous status in Ireland) was declined on May 23, 2007.
I first heard the phrase 'Web 2.0' in the name of the Web 2.0 conference in 2004.
In the Web application domain, making static Web pages accessible is relatively easy. But for Web 2.0 technology, dynamic content and fancy visual effects can make accessibility testing very difficult.
Web 2.0 applications or websites are often very difficult to control by users with assistive technology.