I’ve seen various discussions that have confused or equated privacy (or freedom) with anonymity. Things such as social DRM which marks items with some unique information. There a nice article by Schneier on the differences and relation to security that is worth reading.

As the name implies, Alcoholics Anonymous meetings are anonymous. You don't have to sign anything, show ID or even reveal your real name. But the meetings are not private. Anyone is free to attend. And anyone is free to recognize you: by your face, by your voice, by the stories you tell. Anonymity is not the same as privacy. That's obvious and uninteresting, but many of us seem to forget it when we're on a computer. We think "it's secure," and forget that secure can mean many different things.

The article goes on to discuss the Tor software.