For the most part, I don't collect anyone's data. The only thing kept are server logs.
Past that, however, I really don't want to know or keep tabs on you. If you stick around and become my friend that's different but, then again, that's not a typical web surfer/website relationship.
With that said, if you buy something from me I will, of course, need your contact information and an address. I may hang on to that but, chances are, it'll be written on an old napkin while I make a shipping label and then immediately lost/thrown away/used--thereby rendering my data retention scheme useless. In short, if you buy something else from me you'll probably have to reenter your data.