[See update; a good source tells VentureBeat this story isn’t true, no deal has been closed]

facebooklogo-latest.jpgTwo un-named hedge funds may have invested $250 million each into Facebook, according to Forbes blogger Elizabeth Corcoran.

These deals apparently happened in tandem with the $240 million that Microsoft invested into Facebook, announced yesterday. Corcoran says the hedge funds invested at the same $15 billion valuation as Microsoft.

The numbers, if true, mean that Facebook now has $750 million in the bank. Add that to Facebook’s tight relationship with Microsoft and, finally, a real challenger to Google may be emerging.

Note that Corcoran, who oversees Forbes’ online reporting efforts, works closely with investor Roger McNamee, of Elevation Partners, a large buyout fund in the media industry. McNamee has negotiated with the Facebook founders in the past, offering to help cash some of them out (providing them cash in return for some of their early shares), and so his firm has close ties with the Facebook. Fake Steve Jobs, a satirical blog — not so much a news source — written by Forbes reporter Daniel Lyons, also reported the hedge fund investment. But it has been wrong in the past. For example, it recently said Podtech was closing down. This isn’t true: Paul Matteucci, a partner at US Venture Partners, on Podtech’s board, told VentureBeat this morning that he and the CEO James McCormick “spent a day last week working on the company’s long-term plans. We are having a good revenue quarter and focusing on what’s next. There are certainly no plans to shut down.”)

So it’s important to note that Corcoran, by contrast, is a serious reporter, and is well placed, so we’re assuming she has this right. Facebook responded, to say “no comment.”

Facebook tracks your every move on the site, including which profiles you look at, or so we’ve heard well-placed Facebook employees whisper. “We track usage on Facebook in order to report accurate metrics on growth and engagement,” Facebook replied, when we asked about that.

This means it has a treasure trove of user data and behaviors that it can use to help target Microsoft ads. This data gold mine could turn into the anti-Ad Sense money printing machine that Facebook needs.

Some more tidbits from the webosphere:

The official Microsoft self-congratulatory email to all its employees about the deal, here — “Great job you really pulled this together unbelievably,” Microsoft chief executive Steve Ballmer replied.

The valuation, assuming it pans out to actual money, makes Facebook the fifth most valuable internet company — as Techcrunch points out. It is more valuable than the big Silicon Valley chip maker AMD.

The valuation also makes Facebook founder Mark Zuckerberg worth $5 billion — Valleywag has a source saying Zuckerberg owns around 30 percent of the company, which we’ve also heard.