The Wall Street Journal is reporting (subscription required) that Microsoft has reached a $240 million deal with Facebook for a minority stake. It appears to have put a value of $15 billion on Facebook. The deal opens the way for Microsoft to start selling their ads to the approximately 50 million Facebook's audience.
This is a huge deal for Microsoft and in my opinion levels the advertising playing field somewhat. Google which is dominating the online advertising segment, so it will be interesting to see how this affects in the long term. A lot depends on how Facebook develops and whether it can retain it's audience, something I'm not 100% convinced of yet which may explain why Microsoft ultimately won this bidding war. Did Google sense something that made them offer a lower bid?