Store Loyalty Cards v Deep Packet Inspection

Loyalty cards are now used by many stores to help them understand the buying patterns of repeat customers. In the same way, by using DPI interception equipment deep in the heart of the Internet network, it is possible to track the habits of individuals, building up a profile of their likes, interests and purchasing habits.

Loyalty Cards and Privacy

Do store loyalty cards invade privacy in the same way as ISP hosted deep packet inspection systems?

There is one major difference between the two systems. A store loyalty card only knows what you have bought. The card can not tell the store the path you took through the store to decide on your purchases nor can it tell the store which items you looked at or touched before deciding against purchasing.
The DPI system knows everywhere you have been, it knows how long you spent looking at a page, it knows where you went next, it knows whether or not you visited the shopping cart and it knows when you last looked at something. It knows which search engine you used, it knows the search terms used, it knows which sites you visited and whether or not you filled in a form or visited a forum. The DPI system followed you everywhere and saw what you saw, read what you read, clicked with you to the next page.

What about Cookies?

While you surf there are many tracking sites which save cookies onto your computer. this is so that other pages will be able to report back to sites where you have been before, and whether or not you are a repeat customer. These can only follow you through a very limited number of sites, with the permission of the site hosting the script. Meanwhile the DPI system can see who is storing cookies and collect all the data stored in them. Whichever site you visit, the DPI system forges its own cookies without the permission of the web page so that it too knows that you have been there before.