Lately many websites allow users to sign in using their Google accounts, which seems to be fine, but I am a bit worried about privacy issues...
I have been taking a look, and most of the information I got is about how Google protects your privacy from the sites you sign in, which is indeed very important...
But my question is about the other way around, I mean, when you sign in with Google in a site, what can Google know about that? Obviously it can know that you have an account in there, but can it access any other data about your account in the site?