Maybe I'm in the minority here, but I don't think "fixing" Yahoo ought to be as difficult as people make it seem. It's still a well regarded brand, and many millions rely on it for email and as a homepage. It's finance section remains extremely popular. They purchased Sportacular, the app I use to keep track of games.
Theyve just been very poorly managed. They acquired companies like delicious and Flickr, one they let wilted and the other they never really integrated into their platform- Flickr just feels like a freestanding entity.
They should cut out the garbage that doesnt get many users and should focus on their prized assets. They should push ahead in developing unique content for their viewers. It may be too late to get into the mobile OS game, but TV is still pretty wide open and Yahoo can really do something here, using their existing assets and by further developing or partnering with content providers.
I'm hopeful.