Teen Facebook Users Who Also Use Instagram & Twitter, 2012 [CHART]
In addition to using social networking sites of any kind with greater frequency than teens with relatively small friend networks, teens with a larger number of Facebook friends also tend to maintain profiles on a wider range of platforms outside of Facebook itself.
This is especially true for Twitter use, as teens with more than 600 Facebook friends are more than three times as likely to also have a Twitter account as are those with 150 or fewer Facebook friends. Indeed, some 18% of teens with more than 600 friends on Facebook say that Twitter is the profile they use most often (although some 73% of these teens say that Facebook is their most-used social networking profile). Read the rest at Pew Internet and American Life Project.