The combined platform is expected to reach about 80 million users worldwide.
"AOL is now uniquely positioned to capitalise on the social media space by delivering a more personal experience for consumers and a better way for advertisers to engage them," said Randy Falco, chairman and chief executive of AOL.
"AOL is now fully focused on growing our business in three key areas - advertising network, publishing and people networks - by delivering relevant content and advertising across the web."
Shields's first task as head of People Networks will be to integrate community applications and tools including AIM, ICQ, chat and mail functionality into Bebo.
Products from other recent AOL acquisitions, such as widget technology from Goowy Media and the social search question and answer service from Yedda, will also be integrated into the portfolio.
Prior to joining Bebo 18 months ago, Shields was managing director for Google Europe, Russia, Middle East & Africa, responsible for building and scaling the company's advertising syndication network and establishing content partnerships.