If you don't have a Google account, so you can't log in in the first place, does that mean you have "No Activity", too?
It may be paranoia, but I assume that Google (and, for that matter, Facebook) keeps a dossier of activity emanating from my ISP address, but it's not specifically tied to me as an individual.
Maybe it's because of AdBlock For Safari, but I never see targeted ads; I do, however, get search results that appear to take my ISP address into consideration.
And I"m not the least bit certain that that makes the least bit of sense.