The concept of web2.0 traditionally includes such technologies as web-services, Ajax and content distribution.
Ajax is a relatively new technology, although its operating principle has been known since 1998. That is asynchronous request of a browser for a server. For a user, it looks the following way: you click a link of the page, and in the browser, only a fragment of the page is renewed.
The second important component, without which web2.0 cannot be imagined, is service directivity and content distribution.
The third w2 component is accessibility and support of standards. Yet, currently no browser supports all W3C standards to the full extent.
Apart from the above-listed factors, web2.0 model also includes means of personal content publishing, different blogs, wiki and online-diaries, podcasts, and tags.
Web2.0 is an aspiration to swiftness, interactivity and standardization. This is the user orientation, not the web-site orientation, a possibility of user’s interaction with the content, and not merely presentation of a document to him.