US Twitter Usage Surpasses Earlier Estimates

In 2009, there will be 18 million US adults who access Twitter on any platform at least monthly. That represents a 200% increase over 2008 levels. Usage will reach 26 million US adults in 2010, a further 44.4% climb.

This forecast counts 11.1% of Internet users as Twitter users this year, a figure close in line with Harris Interactive and Pew Internet & American Life Project estimates of 13% and 11%, respectively, in spring 2009. In 2010, eMarketer expects 15.5% of all US adult Web users to use the microblogging service via any platform.

In April, eMarketer estimated that there would be just 12.1 million US adult Twitter users this year. The upward revision is due to growth in Q2 2009 even stronger than the huge gains seen by Twitter in Q1.

In June 2009, for example, Nielsen reported nearly 21 million unique visitors to Twitter.com. That was a year-over-year increase of close to 2,000%, but also an increase over May 2009. Nielsen, comScore and Compete pegged US unique visitors at 18.2 million, 17.6 million and 19.7 million, respectively, that month.

Because many users access Twitter via text messages, mobile apps and various desktop applications, in addition to Twitter.com, eMarketer's estimate of 18 million users for 2009 is somewhat conservative. This is due in part to research indicating low levels of engagement among the majority of Twitter users. (See "Do You Know Who's on Twitter?" for more information.)

"Since our earlier Twitter user estimates were published in April 2009, the number of Twitter.com visitors has risen sharply," said eMarketer senior analyst Paul Verna. "In addition, research data shows healthy—and growing—percentages of US Internet users adopting the popular microblogging platform. These two factors compelled us to upwardly revise our previous forecast.

"At the same time, there are indications that large numbers of users are abandoning Twitter after a short period of experimentation, and another sizable contingent seems to use the service only sporadically. With these trends in place, we felt it was prudent to take a conservative outlook on Twitter's user growth over the next 18 months."