Social network Facebook announced a major facelift yesterday, with the site opening up to third party software by allowing its users to embed an array of applications into their profile pages.

Rival MySpace opened up to outside developers three years ago, but Facebook has until now resisted the move.

But in contrast to MySpace, Facebook says it is taking a non-restrictive approach to the new widget policy – something Snipperoo’s Ivan Pope spoke to us about recently and reckons will become a major differentiator between social networking sites.

CEO Mark Zuckerberg announced the plans yesterday, saying that the developers that will contribute apps to the site will include Amazon, which aims to allow users to show book reviews on their profile pages together with a link to purchase the book.

Facebook trails behind MySpace, with around 23m visitors compared to its rival’s 66m, but it is growing fast, adding 100,000 new users daily. It is the sixth most visited site in the US, as well as having 3.5m users in the UK.  

In the US, the site’s userbase has more than doubled in the last 12 months, while, in the UK, it has grown from 1.6m users in January to 3.6m last month. The site was linked with a $1bn buyout by Yahoo last year, though the price may have risen since then.