A late 2012 survey released Thursday by the Pew Research Center revealed that 67 percent of American Internet users are on Facebook, 16 percent are on Twitter and 15 percent are on Pinterest.
For Pinterest, the 15 percent user number is up from 12 percent in August 2012, suggesting it continues to grow. Instagram placed fourth in the study with 13 percent of American Internet users on the service.
Aaron Pragnell predicted for Forbes back in July that Pinterest "could be the next social media giant." The social media site was showered with praise throughout 2012, beginning in January, when Alicia Eler wrote for RWW that Pinterest was offering an experience that Facebook wasn't.
Notably not mentioned in the Pew report is Google+, which said it was the second most popular social network just last month, based on a study of active users per social network. That said, other studies and likely time-on-site numbers aren't in Google+'s favor. Unlike other social networks, it has the advantage of boosting its numbers with its popular search engine.