piatkow - 1:57 pm on Jun 6, 2009 (gmt 0)
I found a discussion with stats (not here) a long time ago about various techniques for keeping spammers out of forms and mailto links. I can't remember much about it except for two things:
1. A combination of techniques is usually better than relying on a single one
2. (at that time) framing the page containing the form was an effective secondary technique.