Social networking sites have a lot of room to grow on the mobile Web, according to a new report from research firm M:Metrics. In the three months ending this June, an average 7.5 million U.S. wireless subscribers, or about 3.5% of U.S. subs, used a mobile social networking site at least once per month. Even that crowd seems to treat it as a novelty. Just 1.1% visited one at least once a week, and 0.7% used a mobile social network almost every day.
As it does on the Web, News Corp.’s MySpace garnered the biggest audience among mobile social networking sites, with 3.7 million U.S. mobile users. Facebook attracted 2 million people and 900,000 used Google’s YouTube mobile portal.
Of the leaders, MySpace is the only one attempting to make any money off their mobile venture: so far, it’s available exclusively through AT&T for $3 per month (plus data charges) and “virtual” carrier Helio, where it’s bundled into the MVNO’s monthly fee. Facebook and YouTube are free mobile portals with (so far) no ads.