U.S. smartphone users spend an average of four hours and thirty-eight minutes a month browsing the mobile Web, whereas their British counterparts spend about two and a half hours a month, according to a report released by M:Metrics today. The discrepancy in the duration is due to the relative popularity of flat-rate data plans in the U.S.—10.9 percent of users have an unlimited data plan in the U.S. versus only 2.3 percent in Britain. Another factor is that full keyboards are more popular in the U.S. with nine of the ten top smartphones have Qwerty keyboards. What’s especially interesting is that this isn’t an iPhone phenomenon. U.S. smartphone users increased their browsing 89 percent year-over-year, and pageviews have jumped 127 percent. “Consumption is quickly evolving from brief transactions, such as checking the weather or flight status, to time-intensive interaction with mobile Web sites—even without an iPhone,” said Mark Donovan, an M:Metrics analyst. Release.

U.S. mobile browsing favorites by time spent per month (hour:minutes):

-- Craigslist: 1:38
-- eBay: 1:25
-- MySpace: 1:25
-- Facebook: 1:24
-- Disney’s (NYSE: DIS) Go.com: 1:07

U.K. mobile browsing favorites by time spent per month (hour:minutes):

-- Facebook: 1:44
-- Hutchinson’s three.co.uk: 1:30
-- British Sky Broadcasting’s sky.com: 1:15
-- Microsoft’s (NSDQ: MSFT) live.com: 1:11
-- BBC’s bbc.co.uk: 0:48