Loyalty Cards are used to spy on  your purchases, and not just with the vendor

The story of how that Sudafed ad got to me begins at Walgreens. As I bought tissues and Afrin, I keyed in my phone number so I could get loyalty points.

Source: Facebook Really Is Spying on You, Just Not Through Your Phone’s Mic – WSJ

Stores use your loyalty card to identify you and all of your purchases. Your purchase transactions are then sold to other marketing companies. This data, in turn, can and is matched to your Facebook account and other online data using the phone number that you gave to the store and to Facebook or Google.

Think about how Facebook, Twitter and other online services are constantly pestering you to give them your phone number. Once they have your phone number, anything else you do that is linked to your phone number – such as using a loyalty card when buying stuff at Safeway or Walgreen’s is then accessible.

Update: CONFIRMED. Facebook purchases your online retail store purchase data from companies like Axciom, Datalogix, Epsilon and others. FB even says so buried in their anti-privacy policy. Your email address, phone number and possible credit number are used to link your Facebook surveillance logs with your offline purchases.

Everyone is also using the tracking data that Google collects on your Android phone to monitor where you are. Remember, that too is tied to your phone number. As I described on my other blog, the Facebook dossier even tracks what apps you have on  your phone and data mines that to identify potential marketing opportunities.

Google and Facebook are doing highly invasive surveillance and almost no one understands what is being done or what this means.