I want to provide a way for my visitors to contact me but I don't want to use a mailto: link because someone might send me a virus or add me to a spam list. So I thought an email form would be better but I'm concerned about whether or not those can be abused.

I'm wondering what would happen if someone entered an email into the form, clicked send, and then used their BACK button to return to the forum and send the message again... repeating this over and over again until my mail box is flooded with thousands of copies of the same email.

Besides filling my inbox I'm assuming that would also cause problems on the server side. Is there a way of preventing that kind of email flood attack from happening? Maybe a built in "1 post per minute" restriction, or an IP ban of some kind?

I'm not sure if those do exactly what I'm looking for (flood control) but they look like good scripts. If I can't find something like what I want I'll probably go with one of those. Thanks.