Are discounts linked to my credit card spending worth the privacy risk? — Michael, West Bloomfield, Mich.

Both online and off, your purchases often factor into the discounts you're offered. Buy baby food at the grocery store, for example, and you might get a coupon for diapers along with your receipt.

Companies such as FreeMonee and MyLinkables can offer you deals based on your past credit card spending. Details vary, but each has privacy safeguards; Free Monee, for instance, sees where you buy but not your name or specific purchases. Your bank may send you deals from FreeMonee once you've agreed to receive marketing messages, but you can opt out.

If you find tracking creepy — or if a company can't explain clearly how your data is used — skip it. And for real privacy, go off the grid: Clip coupons from the paper, shop at stores, and pay in cash.

— Stephanie AuWerter

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