Have you ever liked a product on Google, or reviewed it favorably? If so, your “endorsement” will now pop up when your friends search for that item. Yes, Google is turning us all into unpaid endorsers.

Google users, you’re about to become shills. A major update to the company’sTerms of Service agreement today could have some users’ profiles showing up in ads across the web. These “shared endorsements,” as Google is calling them, leverage any reviews, comments, +1s, follows or stars a user may have given to a business or brand by effectively placing that user’s name, photo and any relevant comment in a personalized advertisement. It’s worth nothing, however, that if you’ve set restrictions on your shared comments, personalized ads will only be shown to friends within that Google+ circle.

You can opt-out here.

Also relevant is Ryan Calo’s recent article on Digital Market Manipulation. More and more advertisers will use these highly targeted messages to make advertisings more persuasive (and perhaps manipulative).