Smartphone users drive US mobile Twitter growth 347%
Facebook up 112% year-on-year
There's a nice piece of research from comScore, which underlines this.
It's been tracking access in America to social networking sites such as Facebook and Twitter through users' browsers.
It found 30.8 percent of smartphone users have accessed social networking sites during January 2010, up 8.3 points from 22.5 percent one year ago.
Access to Facebook via mobile browser grew 112 percent, while a more recent phenomenon, Twitter experienced a massive 347 percent jump.
What's really significant though is that among users of feature phones, the rise was much less pronounced. Only 6.8 percent of feature phone users accessed social networking sites through their browsers during January 2010.
As for absolute numbers, Facebook has overtaken MySpace as the most popular social app.
In January 2010, 25.1 million mobile users accessed Facebook via their mobile browser, up 112 percent from the previous year.
MySpace attracted 11.4 million users; down from 12.3 million in a year ago. Twitter had 4.7 million mobile users in January 2010.
It's important to note however that these are underestimations of total usage figures as comScore doesn't track access via direct mobile applications, only through mobile browsers.