Many people are worried about the nasty privacy implications — realized and potential — of supermarket and chain store "loyalty" cards. As RFID chips are introduced, things get even more scary.

In an attempt to attack supermarkets’ data-mining operation and to gain a new shopping identity in the process, many people have taken to swapping cards with each other. Over the last few years, I’ve been among these people.

A couple years ago, a few friends and I came up with the idea of creating a sort of online loyalty card swap-meet where people could come and exchange their supermarket or chain-store loyalty cards with total strangers from the privacy of their own homes. Some other people have arranged to swap numbers for particular stores but our idea was to swap the actual cards from any store that uses a card. We actually built most of it but got hung up at the last minute on a couple of details and with writing some of the explanatory text.

Last night, I made the final push and finished the code and set everything up and seeded the database with the lists of as many supermarkets that I know use loyalty cards as listed on CASPIAN’s supermarket list.

If you’ve got an extra card (and maybe if you don’t), go ahead and sign up to swap! This is one of those things that works better when more people do it so tell your friends and spread the word.

Information and the card-swapping apparatus is all online at: