I'm not going to trust memory, mine, yours or anyone's on this and don't have time to traipse back in time to fully research it, but that is besides the point. The point is that Google have form for engaging in privacy violations that extend to the scanning of personal communications for advertising purposes without gaining informed consent (no I don't think click through t&C's that can be changed by Google on a whim count). Worrying that they might do similar with verbal communications for advertising or other purposes is a legitimate concern that shouldn't be dismissed.