Our projects goal was to determine which kinds of sites tend to sell email information, and to contrast that data with common perceptions ("Facebook would never do anything like sell my email..."). We had three accounts sign up for three separate sets of websites, based on what we felt were the common perceptions of how likely a site would sell information. One account only signed up on very popular, big name, well known websites. Another signed up on sites that seemed professional but were less popular and possibly personally owned. The third gave its email address only to sites that were deemed "sketchy" or otherwise likely to be up to something. It should be noted that these groupings were based on our opinions on the sites, specifically, what we thought the average person would "expect" from the site.
We found that our perceptions of which sites would sell emails were pretty accurate. The most nefarious looking websites were more likely to give out our emil info to third parties. Still, few emails were recieved. We postulate that this was partly because our emails were not very valuable, and we did not run the experiment for a long enough period where they would have been properly circulated.
Using gmail, various websites were tested to determine whether they sell email information to third parties.