I like 1 and 4..
1 really pisses them off because even if there are intrested customers, they can't get to the site.
and 4 is just damn funny.
Edit: Oh god i just cracked up about four. Imagine checking your regualr email and there are like 10 thank you notes from porn websites saying something like:
Thank you for registering at freeGoodPorn.com, we really appreciate it. Since you checked the box that it is okay to give your email out to our buissness partners, we will do so. Plus, you will recieve our weekly newsletter, and a picture of the day every day!!! Thank you again.
and you get 10 of those.