Hitwise says that MySpace commands a 72 percent market share of visits to the top ten social networking sites, while Facebook has only gained a 16 percent market share. I find the way Hitwise discloses its data to be confusing-72 percent of what exactly? Why don't they just tell us how many people they think visited the site? We can do our own math.

Any way you slice it, the numbers are surprising. Isn't Facebook supposed to be on a rocket ride? So I decided to look at what comScore has to say on the matter of MySpace versus Facebook (not that they are perfect, but at least they give an actual estimate of how many people they think visited a particular site).

The numbers on comScore corroborate that Facebook is still lagging MySpace, but not by as much as Hitwise would have you think. In December, comScore reports that MySpace had 69 million unique visitors compared to 35 million for Facebook. That would give Facebook about half the market share of MySpace, not one fifth.

Maybe by"visits," Hitwise means page views. Again, the comScore numbers confirm that MySpace is trouncing Facebook in the U.S. with 38 billion page views in December 2007, versus 13 billion for Facebook. Even so, that gives Facebook a third as much "market share" as MySpace. Of course, Hitwise data and comScore data are apples and oranges because they've been collected using different methods and different sources. I offer this more as a gut check.

Regardless of what data better reflects who is winning the social-networking race in the U.S., the real story is happening elsewhere. A peak at the global comScore numbers (as of November 2007) produces this doozy: Facebook has nearly caught up to MySpace with 93 million unique visitors worldwide versus MySpace's 105 million. And in minutes spent on the site, it has actually surpassed MySpace with 21 billion minutes for Facebook versus 17 billion minutes for MySpace. (Although, it is still lagging in page views, 42 billion to 48 billion). The Web is a global game, and MySpace might be about to lose it.