Lauren Indvik reports that mobile users spend more time on social networks than they do on e-mail, a reversal of behavior on desktop computers:

"Mobile users spend 1.4 times as many hours using social networking sites than reading and responding to e-mail, according to a recent study by research company TNS. On average, users spend 3.1 hours per week on social networks, versus 2.2 hours on e-mail."

Indvik writes that in the U.S., desktop users spend 5.1 hours per week on e-mail and 3.8 hours on social networks.