Facebook has unveiled some radical changes that will enable third party developers to build features into the site. The company has apparently signed up 65 partners to develop web applications for the site, including Microsoft and Amazon .

Facebook is the second biggest social networking site on the web. It currently has over 25 million registered users, a number which is growing fast. It differs from other sites in the way that you can only view someone's profile if the other person agrees that you know them.

The recent developments means that Facebook is now more than just a social network site. It's a platform on which licensed developers can build their own web applications

"Until now, social networks have been closed platforms. Today, we're going to end that," said Mark Zuckerberg, Facebook's CEO.

Third party plug-ins

One example of a third party Facebook plug-in is the new Amazon book review feature. It allows you to write book reviews on Amazon, and share them with friends on your Facebook home page.

Facebook has also created some web applications of its own. They include a video sharing tool which enables you to share live video from a web cam, or a camera phone, on your Facebook page.

To add applications to your Facebook page, just log into your account and select 'edit Applications' from the menu bar on the left hand side.

Facebook has recently seen a massive surge in its popularity in the UK, with hundreds of thousands of new members signing up over the past few months.