I'm not this does anything for privacy though. In my tin-foil hat mode, I think they take your data and use it how ever they want. If you have this enabled, they do these "local to you" type of things, and if it is disabled then it goes to the main search. However, that does not prevent them from saving that data linked to you in another table/database. It just means you no longer get the "benefit", but you never prevent Googs from benefiting.