wired has posted a terrific story on why yahoo failed over the last three years. their conclusion, terry semel was too much deal guy and too little visionary. yahoo passed on opportunities to buy google early (they estimate $5 billion was the take out price) and then later youtube and facebook. semel himself is even quoted as saying nobody knows what these companies are really worth. seems to me the company would have fared better with a tim koogle, making bold bets, than an media manager and deal maker.
as a shareholder, i dont count yahoo out. i think they can still go buy the biggest traffic net properties and leverage their ad sales channel to drive high rpm's across multiple properties. i do believe yahoo needs to give up on search (some estimate a $5b accretion in their market cap if they move to google) and be the best at creating and selling net display media.