I'm not so sure it's so clear in that page you linked to. Google do also sell the largest analytics/user-tracking platform that exists (Google Analytics). That page you linked to seems to hinge around what constitutes 'personal information' which I'm sure others have differing opinions about but does go back to the parent's point: Google is in the business of selling your data. It maybe does it in a controlled way, segregating by client properties, or removing certain personally identifying information, but it's still selling your data.