CainIV - 6:47 am on Jun 29, 2006 (gmt 0) I would go that route with most of the live scripts on your site.
Captcha code fixes any indexing form problems or issues with spammers at forms as it requires them validate the number.
On your forum, do you have one of those random number validaors in there, which the user must enter the number to submit? Theat might cut down on all the automated submissions.
I would go that route with most of the live scripts on your site.