11. Google Plus Facebook
Available to those 13+ Available to those 18+
Free; no advertising model (yet) Free; evolving advertising model
Account is an add-on a Google account Account if a separate account that requires
no Google account
62 million users; most inactive? 845 million users; 483 million daily active
(http://www.pcmag.com/article2/0,2817,2398114,00.asp;
http://www.cnn.com/2012/02/28/tech/social-media/google-plus-comscore/index.html) users
(http://www.sec.gov/Archives/edgar/data/1326801/000119312512034517/d287954ds1.htm)