Ok, just filtering based on IP address isn't going to work, as they never seem to be the same twice. It is interesting to see where they come from (most recently the Computer Center of Sharif University of Technology, in Tehran, Iran) but this could be a huge drag.

Suggestions? I realize that filtering based on IP is very 1998, and that these days spammers attack from a huge army of zombie computers, but this is the first time I've have to implement a solution on my own.

I could add one of those "Please enter the text you see below" deals, but I still haven't had time to get the "Name" field to work consistantly...