MySpace. Facebook. Bebo? Call it the triad of free online social networking sites. Bebo touts itself as the largest social network in the UK and the third largest in the US. The site allows users (which are predominantly ages 16-24) to set up profiles through which they can share photos and interests in movies, music, and sports. The company also produces original content, such as Internet soap operas KateModern and Sofia's Diary, and online reality series The Gap Year. The site has about 40 million users. CEO Michael Birch co-founded Bebo with wife Xochi in 2005. AOL bought the firm in 2008.