However, in the last three years something approaching a consensus on what Web 2.0 actually is has emerged. Most agree that Web 2.0 defines the internet as a platform where developers build applications uniquely tailored for the internet, rather than the internet having to adapt to suit the features of applications.

Examples of this definition are wiki sites or Google Docs & Spreadsheets which act like desktop applications but actually work in the user’s browser.

Under Web 2.0, the internet is also seen as a two-way medium with increased interactivity and input for the end user. This can be seen in blogs, wikis and social networking sites where users can easily interact with each other and the website's publisher.

While the term Web 2.0 suggests a newer version of internet, this is not the case. It simply refers to the web as we know it today. And as this will continue to change and evolve—an exact definition of the term may never be possible.

However, there are certain Web 2.0 characteristics that many websites share. These include, but are not limited to, the use of html, xhtml and css; software to support user generated content; application programming interfaces; weblog publishing tools; RSS feeds; wiki software to support user generated content; and the use of open source software.

While millions of websites today have some, or all, of these features, there are a few websites that are thought to have originally been the pioneers of Web 2.0. These include Google, Yahoo, Amazon and eBay.

Today, however, every blog you see and countless other websites can be defined as Web 2.0 sites. The technology is growing fast and certain websites are leading the charge. FaceBook, Wikipedia, Digg and YouTube are all providing popular services and are some of the biggest names in Web 2.0 development.

Perhaps the most important piece of technology in the development of Web 2.0 is the use of AJAX (Asynchronous JavaScript and XML). This allows pages to respond to a user’s actions without reloading the page, making pages more interactive and reducing response times.

Web 2.0 offers some new and innovative ways for individuals and companies to promote themselves, both through marketing and advertising. You will now find multi-national companies using blogs and social networking sites to reach potential customers, while the increasing interactivity of Web 2.0 websites is increasing consumers’ power to voice their opinions.