Google Cloud SVP Diane Greene:
G Suite’s Gmail is already not used as input for ads personalization, and Google has decided to follow suit later this year in our free consumer Gmail service. Consumer Gmail content will not be used or scanned for any ads personalization after this change. This decision brings Gmail ads in line with how we personalize ads for other Google products. Ads shown are based on users’ settings. Users can change those settings at any time, including disabling ads personalization. G Suite will continue to be ad free.
I know I have a fairly hard-line stance on targeted advertising, but I think even the most generous person could agree that Google should never have been using Gmail users’ emails for ad targeting purposes. Even Google seems aware of that — check out the super defensive tone they take in their Gmail ads support article.