Definition of Web 2.0

The term web 2.0 is associated with web applications that facilitate participatory information sharing, interoperability, user-centred 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 of user-generated content in a virtual community,
in contast to websites where users are limited to the passive viewing of content that was created of them.

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 client-side/web browser technologies used in Web 2.0 development are Asynchronous JavaScript and XML (Ajax), Adobe Flash and the Adobe Flex framework and JavaScript/Ajax frameworks such as Yahoo! UI Library, Dojo Toolkit, MooTools and jQuery. Ajax programming uses
JavaScript to upload and download new data from the web server without undergoing a full page reload.

In brief, AJAX is a key technology used to build Web 2.0 because it provides rich user experience and works with any browser whether it is Firefox, Internet Explorer or another popular browser. Then, a language with very web services support should be used to build Web 2.0
applications. In, the language used should be iterative meaning that it will help easy and fast the addition and deployment of features.