Hi MuffinsCanFly, and welcome
It looks like a lot of bases were covered... The only thing I want to say right now is that if a website is going to "sell" your e-mail address, it should be listed in their privacy policy somewhere. Bear in mind that most newsletters, especially those from corporations, usually ask in their subscription form if you'd like to receive mail from their "sponsors or other third-party vendors". That would be one box to keep without a check mark.
As far as trying to tell if a site is telling a lie, that's rather hard to catch. Not sure how you could prove either standpoint on that one.
If you have more questions, don't be afraid to ask