While overall Twitter adoption rates held fairly steady over the past 12 months, that doesn't mean the popularity of Twitter has reached its plateau. According to data from the Pew Research Center's Pew Internet and American Life Project, it all depends on who you ask.The study found that overall adoption of Twitter among online adults in 2012 is 15%, just a bit higher than the 13% of online adults who used Twitter a year ago. However, the frequency (or "intensity" as Pew Research refers to it) of their daily Twitter use has doubled to 8% since 2011 and quadrupled since 2010 (when just 2% of online adults used Twitter on a typical day).Much of the growth in usage intensity can be attributed to the proliferation of smartphones. The study found that 20% of smartphone owners use Twitter, and 16% only use Twitter on their smartphones. In other words, Twitter fits the demands of the mobile audience who like sharing 140-character tweets.Among specific demographic audience segments, Pew Research found that 28% of online African Americans use Twitter and 13% of that audience use Twitter on an average day. Similarly, younger internet users are using Twitter more than other demographic segments with Pew Research reporting that one in three internet users between the ages of 18-24 are using Twitter in 2012. Finally, online internet users in urban and suburban areas are twice as likely to use Twitter than online adults in rural areas.You can follow the links to view the complete Pew Research Center Twitter Use 2012 report or explore the survey questions.Image: Dan Taylor