Jim, I'm a web developer. I in fact wrote my companies tracking system, and it can track pretty much anything you do on a page it's embedded on. However, it's not possible within the confines of JavaScript and cookies to get your email address off your machine. The only way i could get it, would be if you logged into my companies userid system, or you typed it into a form.I'm sure it's tracking cookies.
this is probably it, as all three of these companies have huge affiliate programs.I buy from Ebay, Amazon, NewEgg, etc, so one of those might be affiliated with Kmart.
Such as a reputable company like VW for instance?