Also worth noting that Microsoft wanted to pay half in shares which were worth on Feb 1st 2008 27.20 (post announcement - a huge drop!) - today they are worth 54.42 - almost exactly double.
This means that today if the deal had have gone through (and people kept their MS shares) in 2008, Y! shareholders would have assets worth ~$66bn.
David's point 2 is a good one. It is the reason why bourses insist that a large percentage (IIRC >25% for the LSE) of share capital is in public hands at all times. (Where "public" means people or organisations not associated with the directors or major shareholder.)
