At this point, everyone really needs to decide whether all of their usage of Google services will be linked to their real-life identity, or none whatsoever
For a while I've lived under the illusion that if you sign out, log out from Google, you will be less prone to tracking. That was until I had to fool around with multiple Google accounts for some testing.
When I click "sign out" do you know what the default landing screen is? "Sign in"!
And do you know what that screen shows you? Every single google account you've ever logged into. They know who you are. Every single identity you've created.
So yeah. Logging out or using multiple accounts is no protection. They're still tracking you.
It's like brigade says here: Unless you're all out, you're 100% in as far as Google is concerned.