Just because you pay for content on a site, and are shown no ads on that site, doesn't mean that site can't make money from ads on your presence. Isn't the val

Just because you pay for content on a site, and are shown no ads on that site, doesn't mean that site can't make money from ads on your presence. Isn't the value for online ads in following you around, and showing you targeted ads all over the place? Why couldn't a site just sell the fact of your presence and use on a site to advertisers, including your habits while on the site? You could still be shown targeted ads elsewhere, and probably never connect it with your use of the original site.