YHOO is way over priced. The company's business is worth about $6 to $7 per share.
The reason MSFT is down 20% is because it scared Wall St that MSFT could be so stupid as to want to overpay by a mile for YHOO.
Going forward MSFT needs to fire Balmer for his recklessness about YHOO. Gates needs to come out of retirement and work as interim CEO. Gates needs to hire a new CEO from within or outside the company. The new team needs to spend Microsoft getting Micorsoft's internet business lines current and cutting edge.