Word on the street has it that Microsoft stole the Facebook deal from Google with a $240 million investment for 1.6% of the company. If Microsoft's investment is indicative of what Facebook is worth, its valuation is somewhere in the ballpark of $15 billion. It's a bit strange seeing Microsoft actually prevail in a bidding war against Google. Perhaps Google didn't want the overpriced company bad enough -- $15 billion is an interesting valuation considering it would put each user profile on Facebook at around the $314 mark.
$240 million really isn't that much. Especially when $750 million was the going figure for the longest time. In terms of Google's cash flow, a company accountant could trip coming out of the bathroom and drop that much cash. It's safe to say that Microsoft was the highest bidder because it wanted this particular investment more. That's not to say that Google turned its nose up at Facebook entirely. The interest was there -- just not at Facebook's asking price. -- Wired Blogs
This "small" investment guarantees Microsoft's position as the sole advertising provider for Facebook in the United States and internationally.