@Latte31 - I know that some companies will use a rewards or customer loyalty card in order to track purchases and also send you promotional emails regarding targeted offers.
Many supermarkets and drug stores do this. Once you fill out a reward card application they track every purchase and may send you additional coupons based on the email that you provided.
One supermarket in particular requires its customers to sign up for the reward card in order to receive the sales offered throughout the store. This way if you don’t sign up for the card, you will have to pay the regular price for everything. Most people when faced with this situation fill out the card and the company develops its email marketing lists.