This is for supermarkets, but the same general principles apply:

http://www.theguardian.com/money/2013/jun/08/supermarkets-ge...

>If you have a loyalty card or shop online, the supermarkets will build up a demographic profile of you, and collect data about how loyal you are, what you buy and how much you spend, says Guy Montague-Jones of The Grocer.

This is how retail in America works now: collect data, adjust to fit.