As of February 2012, some 15% of online adults use Twitter, and 8% do so on a typical day. Overall Twitter adoption reamins steady, as the 15% of online adults who use Twitter is similar to the 13% of such adults who did so in May 2011. At the same time, the proportion of online adults who use Twitter on a typical day has doubled since May 2011 and has quadrupled since late 2010—at that point just 2% of online adults used Twitter on a typical day. The rise of smartphones might account for some of the uptick in usage because smartphone users are particularly likely to be using Twitter.
Read the full report, Twitter Use 2012, on the Pew Internet & American Life Project website.