I couldn't agree more with your comment. Maybe there is a way to collect data about user only after they have been anonymized, so the data would contain only what user_xxx does, with no way to map user_xxx to his real identity.
I don't think it's trivial, but I hope to see some regulations coming in the way the data are collected and stored.
EDIT: I'm also one of those guys who's like "no I'm not signing up to X service because they don't need more data about me" but I get the double-edged sword and how more of the right data makes certain decisions easier.