Facebook is the number one social network in the United States, according to metrics firm Experian Hitwise. Mark Zuckerberg and company captured almost 59 percent of all US-based web traffic among the top social networks. Are you shocked? I know I'm not.

Hitwise recently released its social networking website traffic report for September 2009, measuring a total of 155 online destinations.

While Hitwise comes to some unsurprising conclusions, like Facebook's prominence, the report does make some interesting suggestions. By the numbers, Facebook looks like it really is the Google of social networks, but MySpace may offer more activities, and Twitter is proving impossible to measure.

But First, the Numbers

Hitwise put together a list of 155 social networks to measure US-based traffic among popular social networks. Facebook was first with 58.59 percent of American traffic; MySpace came in second with 30.26 percent; Tagged was a distant third with a dismal 2.38 percent; and Twitter and myYearbook rounded out the bottom five with 1.84 and 1.05 percent, respectively.

Among other numbers Hitwise produced, it was interesting to note that U.S. users spend the most time at MySpace for an average visit of 25 minutes and 56 seconds. The rest of the top five ended up in this order: Tagged (25:17), Facebook (23:00), myYearbook (18:07) and Twitter (15:52).

I Don't Know; Facebook It

Facebook is on its way to becoming Google, at least in terms of the social network's popularity. I think we've all known for some time that Facebook is at the top of the pack when it comes to social networks, but Hitwise's numbers remind us of how far Facebook is ahead of its competitors. People weren't even talking about Facebook when News Corp. acquired MySpace in 2005, but how quickly times change. Now, Facebook looks set not only to be the leader, but the dominant social network in the United States. In fact, these numbers are looking more and more like a traffic listing for search engines.

ComScore's search rankings for August 2009 put Google at the top with 64.7 percent of US search traffic, followed by Yahoo at 19.3 percent and Microsoft at 8.9, with Ask and AOL bringing up the rear at less than 4 percent each.