Web 2.0 is a mix of emerging and existing technologies.

The key principles of web 2.0 applications are viewing the web as a platform where information is the most important element and driving force.

Web 2.0 is user centered, Web 2.0 sites are composed of elements which are collected from distributed independent users.

Therefore a basic Web 2.0 website needs to display some basic characteristics before it can be classed as a web 2.0 service.

These include

• allowing the site’s services to be accessed entirely through web browsers.
• rich, user-friendly interface
• social networking features such as blogs, wikis etc.
• user participation
• user content contribution, which means that the users own the site’s data, is a key characteristic of a web 2.0 site.

The most prominent technology of web 2.0 is Ajax which is short for Asychronous JavaScript and XML.

Ajax is a web development technique used for developing interactive web applications where content can be downloaded and uploaded from and to a web server from within a web page without having to reload the web page.

Ajax allows developers to create web applications and Rich Internet Applications (RIA) where quick incremental updates are made to the page without the page needing to be reloaded.

RIA can be described as web applications which have the features and functionality of desktop applications and result in a more effective and responsive user experience for the end user.

Therefore RIA are run in web browsers and do not require any software installation on the clients computer.

A Web 2.0 website can also make use of RSS technology which is short for Really Simple Syndication, Rich Site Summary or RDF Rich Summary.

This RSS is an XML format for syndicating, in other words sharing, web content among different web sites.

Any website that wishes to allow other sites to publish some of its content creates an RSS document and registers this document with an RSS publisher and any user that can read RSS content can use this content on some other site.

RSS content can include such information as

• news feeds
• stories,
• event listings
• any other information specific to a particular context,
• technological developments
• emerging technology trends, which they may wish to make available to users.

A major technological feature of a Web 2.0 website is the use of wiki software.

Wiki software allows anyone using a web site to add, remove and edit content on a site and the content is accessed through a web browser.

Wiki software helps facilitate collaboration among users of a site as the focus of wiki software is content rather than presentation.