The one privacy control that everybody is waiting for is: automatically delete all my activity data older than N days, where N can be specified by the user.
While allowing them to specify a minimum and/or incremental value for N.
They're a business after all, and our data is their value.
I'd be happy with that compromise.
I expect minimal value of N to be either sky high, or decent..with plenty of exceptions written in ToS so that it dosen't do anything - just like most 'out out' forms in other sites that always 'fail' to deliver your opt out.