One of the many gems from this article. If that’s not enough for you they also have a little flash applet that represents the struggles between microsoft and yahoo as a game of battleship
…The question was how to prevent what happened at Microsoft from happening at Google. Consumers have had more choice on the internet. And we have a set of policies that we follow—entrenched inside the culture—the most important of which is that we won’t trap user data in proprietary systems. So we have a rule: You have to make it possible for people who don’t like your service to get out. If I don’t like Google, I can switch to Yahoo, Microsoft, or whatever. This has another impact that’s not as obvious. It serves as a check and balance on poor-quality teams. They can’t prevent users from fleeing bad products. It also helps us with this question of becoming too big and powerful.