After days of rumours, the announcement was finally made yesterday: Microsoft has just paid $240 million USD for 1.6 percent of social-networking juggernaut Facebook, which makes Facebook worth $15 billion dollars. This makes Facebook the 5th most valuable US Internet company (Google is #1, followed by eBay, Yahoo, and Amazon).

Google was apparently also in the running for a piece of Facebook, and there is plenty of speculation going around as to why they were snubbed in favour of Microsoft. The simple reason is of course, that Microsoft had already invested significantly in the social-network startup when they bought the exclusive rights to sell FB's advertising inventory, and they had already agreed to work together on future technology and advertising initiatives.