The shift from static business-to-consumer (B2C) Web sites to interactive B2C Web sites - essentially the evolution from Web 1.0 to Web 2.0 - has paved the way for increased interactivity between businesses and consumers. Those businesses that can deliver on the promise of a more engaging, meaningful, and useful experience have the opportunity to strengthen their consumers loyalty to the brand. However, without being able to rapidly, reliably, and securely deliver rich interactive content, the benefits afforded by this new level of interactivity will go unrealized.

Many enterprises have long relied upon content delivery networks (CDNs) to help ensure the scalability, performance, and availability of their static Web sites. Unfortunately, traditional CDNs have not evolved to meet the delivery challenges posed by today´s sophisticated interactive content.

A profound change is happening on the cutting-edge of web development: we are relinquishing control of information. No longer are sites working independently from each other; no longer is information sitting in isolation with no interaction between sites. Rather, the best web programmers are now creating sites that allow information to be reused anywhere. This means you can include the BBC´s latest news headlines on your site. It means people can keep track of your job vacancies on their desktop. It means instead of having a static map on your contact page you can include a map from Google that can be annotated, dragged around, and zoomed in and out. Ultimately, it means people will no longer need to get your information directly from your web site. That may sound terrifying to some but once you embrace this new paradigm its benefits become obvious. Welcome to the world of Web 2.0.

Web 2.0 is a new methodology for creating a web computing platform.Web 2.0 technologies have been described as new and emerging technologies. Technologies such as on-demand video, file sharing, blogs, wikis, and pod casting have become very popular with language educators and students. Users of these technologies have emphasized their collaborative and community-building aspects, and suggested they are a natural ally for a constructivist learning methodology. A number of events sponsored 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.

The moniker Web 2.0 is misleading; it isn´t a new version of the web but a new methodology for creating a web-computing platform. The term was first used by Dale Dougherty of O´Reilly Media while developing ideas with Craig Cline of MediaLive for a technical conference. Dougherty suggested that the web was in a renaissance; while it´s hard to believe something at most fifteen years old is in need of a rebirth it is certain that Web 2.0 is an evolution of the web as it mostly is now. Web 2.0, a phrase coined by O'Reilly Media in 2003 [1] 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."

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 management systems 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

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. 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").

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").

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.

Some basic common characteristics. These might include:

• "Network as platform" delivering (and allowing users to use) applications entirely through a browser. See also Web operating system.
• 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 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.
• 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 tag clouds, 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 organizations and domains
• Web log publishing
• Mashups
• REST or XML Web services APIs

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 POST ing 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). The technologies that allow this to happen already exist; the most important being XML-based syndication and aggregation using RSS and Atom, rich-application support (the web´s current beau in this field is AJAX), and using URLs as a command-line.

Web 2.0 can be summarised thus:

• The web is a platform: just as software is released for Microsoft Windows so to will software be released for the web.
• Data is the focus of everything.
• Build an architecture of participation: that is, systems are designed for user contribution
• Sites are composed of features pulled from distributed and independent developers
• It has lightweight business models;
• Continual, automatic almost invisible software updates rather than a software adoption cycle.