Google mailer has some wondering if the promise of gift cards is real

A strange flyer from Google arrived in mailboxes recently and had some Michigan consumers wondering what was up.

Google apparently is promising gift cards — if consumers who receive such mailers agree to enroll their smartphones to start sharing all their web and app activity for a "Device Usage Study."

You'd get $20 — or 2,000 in points — for signing up. Over time, you might be able to earn up to $540 —or 54,000 in points — during a year for each participant in your household. (The program notes that 100 points are worth $1.) You can earn points each week and redeem the points for gift cards.