With a large portion of traffic still coming from college-age users (40% between 18 and 24), Hitwise says the drop could be tied to school-year schedules. But it also suggests the decline could reflect growing disenchantment with a torrent of friend and application invites on Facebook.
The site also made it easier this month for people to quit membership. The Hitwise data follows comScore's January report showing a slight dip in Facebook's traffic. But it looks like the site experienced a similar mid-winter lull last year before resuming steady growth for the rest of 2007. So don't give up your Scrabulous game just yet.
--Mark Walsh