If Microsoft's management has any active neurons firing, they should let sleeping Yahoo deals lie. Why? Consider what I wrote about Delicious: Yahoo insisted on a rewrite from Perl to PHP, which is why the project went dormant for three years.

Now consider all the systems Microsoft would get in an acquisition that they would have to make mothball/rewrite decisions on. And before you say "no, they could leave those systems as-is", just consider the notion of Microsoft, Windows vendor, having major internet properties on Linux.

If they go through with it, much of Yahoo will die quickly, and the rest will die slowly.