Paul Graham on Yahoo!

“In technology, once you have bad programmers, you’re doomed. I can’t think of an instance where a company has sunk into technical mediocrity and recovered. Good programmers want to work with other good programmers. So once the quality of programmers at your company starts to drop, you enter a death spiral from which there is no recovery.”

What Happened to Yahoo
http://www.paulgraham.com/yahoo.html