Actually, Google does have one major challenge -- how to motivate its people. I'm not talking about fresh college graduates, but rather people who are high up in the organization because they happened to join early on. Many of these people are worth a lot of money, and presumably see day to day work at Google as a way to spend their time, socialize, and to flex their political muscle.

In such a place, bringing in new hungry blood is very difficult to do, especially since the old crowd will try very hard to protect their power structure. In the long term, this does cause problems in the ranks, since success within the company starts to become a measure of how well you can navigate politically, vs. the quality of work produced.