I realised today when signing in, that everytime i use my computer I send some data back and forth to the Ubuntu One service, for obvious reasons, and that would actually mean Canonical could save us users data, like when we use our computers and how, and (if the Ubuntu One-folder on the server ain't encrypted in a good manner) what content we want to save in the cloud, and since Ubuntu One is not open source, we, the community, can't check if Canonical logs more than we are comfortable with.
Don't get me wrong, I'm no conspiracy nut, just courious :).