However, I may be wrong; I only recall one instance of this happening with Buzz, and may simply have missed other ones.
Other times when google violated privacy which I remember: 1) Accidentally logging packets, which they then told people about and found a good way to delete, instead of just pretending it didn't happen. 2) Releasing emails (and other information?) to governments when required to do so by law, which I consider a valid excuse.
Google tries to reach the unevil side, by giving you as full control of your data as they can, and not cross over the creepy line (although they are always near it).
Facebook doesn't, and therefore finds itself on the evil side almost all the time. It's not that they want to be evil that makes them evil; It's just that not avoiding becoming evil makes them that way, and they do not try to avoid it in any way. (Plus, evil is more lucrative).