I think I've seen this in play in some places already. Google itself actually had a nag on every page when they changed their T&C for non-logged in users. I didn't pay attention to how the transition was handled from Anonymous to signed in there as I always sign in.
But, you could do the same and where they "accept" T & C, log them in so that you can update their user record so that they don't get bothered when logged in but the little Nag stays up in the upper right corner till all of your legacy users are accounted for. Then you can remove it as all new users agree to the revised T&C on sign-up.
Firefox has privacy settings that allow you to select cookie deletion on exit as an option. It is a user activated thing. Anonymizer was an early add-on that offered this and it was later folded into the privacy settings.
I think I've seen this in play in some places already. Google itself actually had a nag on every page when they changed their T&C for non-logged in users. I didn't pay attention to how the transition was handled from Anonymous to signed in there as I always sign in.
But, you could do the same and where they "accept" T & C, log them in so that you can update their user record so that they don't get bothered when logged in but the little Nag stays up in the upper right corner till all of your legacy users are accounted for. Then you can remove it as all new users agree to the revised T&C on sign-up.
Firefox has privacy settings that allow you to select cookie deletion on exit as an option. It is a user activated thing. Anonymizer was an early add-on that offered this and it was later folded into the privacy settings.