Move over, MySpace. Facebook is the new king of social media.

News Corp.'s (NYSE:NWS) darling online hangout used to be the most-visited Web site in the world, but according to the latest comScore report, Facebook simply outgrew the former regent way back in April, and its onslaught shows no sign of relenting.

Facebook welcomed 132 million users in June, three times its gate count from June 2007. MySpace grew, too, but only by a paltry 3%, stopping at 117.6 million visitors. With growth deltas like that, it was only a matter of time before the cape and scepter passed to a new ruler.

And there are no serious usurpers in Facebook's rearview mirror, either. Privately held Friendster increased its traffic by 50%; Google's (NASDAQ:GOOG) Orkut tacked on 41%; and Time Warner (NYSE:TWX) property Bebo could only manage 32% year-over-year growth. Well, okay, hi5 doubled in size, but I'm not sure that counts -- that service automatically invites your entire address book when you sign up, and it's working to address some other spam-related problems its users have encountered.

So when will Facebook go public, so we can invest in this insane growth story? Probably not until the current financing crunch is over.  But it will happen. Google might have been happier out of the public scrutiny that comes with a IPO, Sarbanes-Oxley, and all the rest -- but it really had no choice. Once the search giant grew big enough to hand out enough stock options to its employees, it knew it might as well shake the money tree and sell some stock, too. Think of Facebook as Google reincarnated, a year or two before the IPO.

That is, unless somebody buys Facebook wholesale first. Are you game, Microsoft (NASDAQ:MSFT)? You already own a small slice of this pie, and you look hungry for more. How about you, Cisco (NASDAQ:CSCO)? Your habit of buying your way into consumer markets is well-documented, and you've got lots of cash to spare. Hey, Steve Jobs -- maybe Apple (NASDAQ:AAPL) wants to marry Facebook's massive traffic with the money-making mojo of iTunes? The opportunities look endless!

Further Foolishness:

Microsoft is a Motley Fool Inside Value selection. Google is a Motley Fool Rule Breakers pick. Apple is a Motley Fool Stock Advisor recommendation. Try any of our Foolish newsletter services free for 30 days.

Fool contributor Anders Bylund is a Google shareholder, but he holds no other position in any of the companies discussed here. You can check out Anders' holdings if you like. Foolish disclosure thinks of Facebook as the world's biggest address book.