It should be no surprise, but Facebook's dominance as the social network of choice for young adults is unparalleled -- boasting a user base nearly double that of its closest rival, Google+.
According to a recent study from the Institute of Politics at Harvard University, 84 percent of 18- to 29-year-olds in the U.S. have a Facebook account, compared to 44 percent who are signed up on Google+. In third and fourth place, Twitter has 40 percent and Instagram, a Facebook property, has 36 percent.
Further down on the list is Pinterest (33 percent), Snapchat (23 percent) and Tumblr (14 percent). At the bottom are WhatsApp (9 percent) and Foursquare (6 percent).
Though it may still dominate, Facebook's lead seems to be slipping, and the social network's executives admitted last year that it had lost younger users. And in January, digital consultancy iStrategyLabs released a study that found that Facebook has lost 4.2 million high-school-age users and 7 million college-age users since 2011.