Mark it on your calendar - April 19, 2008 - the date that Facebook overtook Myspace as the #1 social networking site on the Web.
This has been a long time coming. Facebook has been steadily increasing reach while Myspace has been treading water. Over the course of the last 8 months facebook has seen its unique visitors double, growing its reach from 4% in September of last year to 8% today... an impressive achievement by any measure.
As of this writing, Facebook is ranked as the 5th most popular site on the web, just ahead of Myspace at #6. This puts Facebook ahead of Internet heavyweights such as Wikipedia (#8) and MSN.com (#7).
Can facebook move up farther in the rankings to #4? Not anytime soon. The site currently in that position is live.com, which has more than twice the number of visitors. But who knows, at this growth rate, facebook may not be done scaling the Alexa rankings.