Social networking activity comprises more than half the time spent on the mobile internet in the US

"Social networking activity comprises more than half of the time spent on the Mobile Internet, reports survey from Ground Truth. The report also noted that users of mobile-specific social networks are more engaged than users of PC-based social networks, such as Facebook and MySpace, on mobile.
"While the popularity of mobile social networking is widely believed, this is the first time we have been able to truly quantify just how much the category is driving adoption of the Mobile Internet with actual usage metrics," said Evan Neufeld, vice president of marketing, Ground Truth. "The disparity of time spent between social networking and the next category, portals, which account for 59.83 and 13.65 percent of time spent respectively, is a vivid illustration of the impact social networking has on Mobile Internet traffic in a given week."
Beyond sheer usage trends in social networking, data for the week ending April 4 indicates that mobile-centric social networking sites such as MocoSpace and AirG are better at engaging consumer than are with PC heavyweights like Facebook and MySpace."
Source: Ground Truth, reported in Cellular News, April 2010