After two failed attempts to create a Facebook killer with Yahoo 360 and Mash, Yahoo will now revamp its content across all of its websites to create a social network atmosphere.

The plan is to allow users to create profiles, similar to Facebook and MySpace, and add widgets made by outside developers to almost any page. Yahoo will also highlight emails from the friends you talk to the most frequently and track your pals’ online activities, similar to FriendFeed.

''We are going to rewire the entire experience at Yahoo to make it social in every dimension,'' said Ari Balogh, Yahoo's chief technology officer, at the Web 2.0 Expo in San Francisco on Thursday.

The changes will take place by the end of the year.