WEB 2.0

Web 2.0

A second phase in the evolution of the World Wide Web where developers use new technologies to create websites that look and act like desktop programs and encourage collaboration and communication between users. Blogs, E-Mail Newsletters and RSS Feeds are just a few of the new technologies Web 2.0 technology offers.

· a resurgence in the web economy · a new level of technological interactivity between web sites and services or social phenomena deriving from new types of online communities and social networks

Web 2.0, a phrase coined by O'Reilly Media in 2003 and popularized by the first Web 2.0 conference in 2004, refers to a perceived second-generation of Web based communities and hosted services such as social networking sites, wikis and folksonomies that facilitate collaboration and sharing between users. O'Reilly Media titled a series of conferences around the phrase, and it has since become widely adopted.

Though the term suggests a new version of the Web, it does not refer to an update to World Wide Web technical specifications, but to changes in the ways systems developers have used the web platform. 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."

Some technology experts, notably Tim Berners-Lee, have questioned whether one can use the term in a meaningful way, since many of the technology components of "Web 2.0" have existed since the beginnings of the World Wide Web.

Contents
1 Introduction
2 Characteristics of "Web 2.0"
3 Technology overview
4 Innovations associated with "Web 2.0"
4.1 Web-based applications and desktops
4.2 Rich Internet applications
4.2.1 Server-side software
4.2.2 Client-side software
4.3 XML and RSS
4.3.1 Specialized protocols
4.4 Web protocols
5 Web 2.0 and Language Learning Technologies
6 Criticism

Introduction

The phrase "Web 2.0" hints at an improved form of the World Wide Web; advocates suggest that technologies such as weblogs, social bookmarking, wikis, podcasts, RSS feeds (and other forms of many-to-many publishing), social software, Web APIs, Web standards and online Web services imply a significant change in web usage.

As used by its supporters, the phrase "Web 2.0" can also refer to one or more of the following:
The transition of web sites from isolated information silos to sources of content and functionality, thus becoming computing platforms serving web applications to end-users
A social phenomenon embracing an approach to generating and distributing Web content itself, characterized by open communication, decentralization of authority, freedom to share and re-use, and "the market as a conversation"

Enhanced organization and categorization of content, emphasizing deep linking
A rise in the economic value of the Web, possibly surpassing the impact of the dot-com boom of the late 1990s

Earlier users of the phrase "Web 2.0" employed it as a synonym for "Semantic Web", and the two concepts do complement each other. The combination of social-networking systems such as FOAF and XFN with the development of tag-based folksonomies, delivered through blogs and wikis, sets up a basis for a semantic web environment.

Tim O'Reilly regards Web 2.0 as business embracing the web as a platform and utilising its strengths (global audiences, for example). O'Reilly considers that Eric Schmidt's abridged slogan, don't fight the Internet, encompasses the essence of Web 2.0 — building applications and services around the unique features of the Internet, as opposed to building applications and expecting the Internet to suit as a platform (effectively "fighting the Internet").

On September 30, 2005, Tim O'Reilly wrote a piece summarizing the subject. The mind-map pictured above (constructed by Markus Angermeier [5] on November 11, 2005) sums up the memes of Web 2.0, with example-sites and services attached.In the opening talk of the first Web 2.0 conference, Tim O'Reilly and John Battelle summarized what they saw as key principles of Web 2.0 applications:

the web as a platform
data as the driving force
network effects created by an architecture of participation
innovation in assembly of systems and sites composed by pulling together features from distributed, independent developers (a kind of "open source" development)
lightweight business models enabled by content and service syndication
the end of the software adoption cycle ("the perpetual beta")
software above the level of a single device, leveraging the power of The Long Tail. ease of picking-up by early adopters

Tim O'Reilly gave examples of companies or products that embody these principles in his description of his "four plus one" levels in the hierarchy of Web 2.0-ness:

Level 3 applications, the most "Web 2.0," which could only exist on the Internet, deriving their power from the human connections and network effects that Web 2.0 makes possible, and growing in effectiveness the more people use them. O'Reilly gives as examples: eBay, craigslist, Wikipedia, del.icio.us, Skype, dodgeball, WorkACE and Adsense. Level 2 applications, which can operate offline but which gain advantages from going online. O'Reilly cited Flickr, which benefits from its shared photo-database and from its community-generated tag database. Level 1 applications, also available offline but which gain features online. O'Reilly pointed to Writely (since 10 October 2006: Google Docs & Spreadsheets, offering group-editing capability online) and iTunes (because of its music-store portion). Level 0 applications would work as well offline. O'Reilly gave the examples of MapQuest, Yahoo! Local, and Google Maps. Mapping applications using contributions from users to advantage can rank as "level 2". Non-web applications like email, instant-messaging clients and the telephone.

Characteristics of "Web 2.0"

This section overlaps with other sections; it should be combined with the rest of the article.
While interested parties continue to debate the definition of a Web 2.0 application, a Web 2.0 web-site may exhibit some basic common characteristics.

These might include:
"Network as platform" — delivering (and allowing users to use) applications entirely through a browser. Users owning the data on the site and exercising control over the data. An architecture of participation that encourages users to add value to the application as they use it.This stands in sharp contrast to hierarchical access-control in applications, in which systems categorize users into roles with varying levels of functionality. A rich, interactive, user-friendly interface based on Ajax or similar frameworks. Some social-networking aspects. Enhanced graphical interfaces such as gradients and rounded corners (absent in the so-called Web 1.0 era). 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.

The concept of Web-as-participation-platform captures many of these characteristics. Bart Decrem, founder and former CEO of Flock, calls Web 2.0 the "participatory Web" and regards Web-as-information-source as Web 1.0.

Technology overview

The complex and evolving technology infrastructure of Web 2.0 includes server-software, content-syndication, messaging-protocols, standards-based browsers with plugins and extensions, and various client-applications. These differing but complementary approaches provide Web 2.0 with information-storage, creation, and dissemination capabilities that go beyond what the public formerly expected of websites.

A Web 2.0 website may typically feature a number of the following techniques:
Rich Internet application techniques, optionally Ajax-based CSS
Semantically valid XHTML markup and the use of Microformats
Syndication and aggregation of data in RSS/Atom
Clean and meaningful URLs
Extensive use of folksonomies (in the form of tags or tagclouds, for example)
Use of wiki software either completely or partially (where partial use may grow to become the complete platform for the site)
Use of Open source software either completely or partially, such as the LAMP solution stack XACML over SOAP for access control between organisations and domains
Weblog publishing
Mashups
REST or XML Webservice APIs

Innovations associated with "Web 2.0"

Web-based applications and desktops

The richer user-experience afforded by Ajax has prompted the development of web-sites that mimic personal computer applications, such as word processing, the spreadsheet, and slide-show presentation. WYSIWYG wiki sites replicate many features of PC authoring applications. Still other sites perform collaboration and project management functions. In 2006 Google, Inc. acquired one of the best-known sites of this broad class, Writely.

Several browser-based "operating systems" or "online desktops" have also appeared. They essentially function as application platforms, not as operating systems per se. These services mimic the user experience of desktop operating-systems, offering features and applications similar to a PC environment. They have as their distinguishing characteristic the ability to run within any modern browser.

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 slightly more than the total it had raised in venture capital after six years of trading.

Rich Internet applications

Main article: Rich Internet applicationRecently, rich-Internet application techniques such as Ajax, Adobe Flash, Flex, Nexaweb, OpenLaszlo and Silverlight have evolved that can improve the user-experience in browser-based applications. These technologies allow a web-page to request an update for some part of its content, and to alter that part in the browser, without needing to refresh the whole page at the same time.

Server-side software

The functionality of Web 2.0 applications builds on the existing Web server architecture, but relies much more heavily on back-end software. Syndication differs only nominally from the methods of publishing using dynamic content management, but web services typically require much more robust database and workflow support, and become very similar to the traditional intranet functionality of an application server. Vendor approaches to date fall either under a universal server approach (which bundles most of the necessary functionality in a single server platform) or under a web-server plugin approach (which uses standard publishing tools enhanced with API interfaces and other tools).

Client-side software

The extra functionality provided by Web 2.0 depends on the ability of users to work with the data stored on servers. This can come about through forms in an HTML page, through a scripting language such as Javascript, or through Flash, Silverlight or Java. These methods all make use of the client computer to reduce server workloads and to increase the responsiveness of the application.

XML and RSS

Advocates of Web 2.0 may regard syndication of site content as a Web 2.0 feature, involving as it does standardized protocols which 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 which permit 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. Increasingly, these technologies are becoming known as Web feed as the usability of Web 2.0 evolves and the RSS icon replaced by the more user-friendly Feeds icon.

Specialized protocols

Specialized protocols such as FOAF and XFN (both for social networking) extend the functionality of sites or permit end-users to interact without centralized web-sites. (See microformats for more specialized data formats.)

Web protocols
Web communication protocols support the Web 2.0 infrastructure. Major protocols include REST and SOAP.

REST (Representational State Transfer) indicates a way to access and manipulate data on a server using the HTTP verbs GET, POST, PUT, and DELETE

SOAP involves POSTing XML messages and requests to a server that may contain quite complex, but pre-defined, instructions for the server to follow In both cases, an API defines access to the service. Often servers use proprietary APIs, but standard web-service APIs (for example, for posting to a blog) have also come into wide use. Most (but not all) communications with web services involve some form of XML (eXtensible Markup Language).

Web 2.0 and Language Learning Technologies

In second language learning, Web 2.0 technologies have been described as new and emerging technologies. Technologies such as on-demand video, file sharing, blogs, wikis, and podcasting have become very popular with language educators and students. Users of these technologies have emphasised their collaborative and community-building aspects, and suggested they are a natural ally for a constructivist learning methodology. A number of events sposored by the IATEFL Learning Technologies SIG in the UK, Japan and India have focused on the use of Web 2.0 technologies to enhance language learning environments.

Criticism

Given the lack of set standards as to what "Web 2.0" actually means, implies, or requires, the term can mean radically different things to different people.

Many of the ideas of Web 2.0 already featured 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.[12] Previous developments also came from research in computer-supported collaborative learning and computer-supported cooperative work and from established products like Lotus Notes and Lotus Domino.

Conversely, when a website is proclaimed "Web 2.0" for the use of some trivial feature (such as blogs or gradient-boxes) observers may generally consider it more an attempt at promotion than an actual endorsement of the ideas behind Web 2.0. "Web 2.0" in such circumstances has sometimes sunk simply to the status of a marketing buzzword, like "synergy," that can mean whatever a salesperson wants it to mean, with little connection to most of the worthy but (currently) unrelated ideas originally brought together under the "Web 2.0" banner.

The argument also exists that "Web 2.0" does not represent a new version of World Wide Web at all, but merely continues to use "Web 1.0" technologies and concepts. Note that techniques such as AJAX do not replace underlying protocols like HTTP, but add an additional layer of abstraction on top of them.

Other criticism has included the term "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. The Economist has written of "Bubble 2.0."

Venture capitalist Josh Kopelman noted that Web 2.0 excited only 53,651 people (the number of subscribers to TechCrunch, a Weblog covering Web 2.0 matters), too few users to make them an economically-viable target for consumer applications.

Source: Wikipedia and other websites.....