Now if you think Captcha is the ultimate solution to block any spammers in your blogs, forget it. You have solved only half of the problem.
A good friend Brian Delahunty (who has also started a very dynamic user group INDA SouthEast in Ireland) spent some of his precious time on developing a solution which work well against the spams coming from the trackback.
I already installed the Trackback spam blocker for .Text in Developers.ie blogs and so far not a single spam in my comments.
Also if you are a member of INDA and you use a blog under developers.ie let me know if you need more keywords to be added to the filter. See below but at the moment I am using the same pattern than Brian recommend.
From Brian latest post:
Well, my Trackback Spam Blocker for .Text[^] seems to be working perfectly at the moment. I've just got 23 emails from the spam blocker detailing what it has blocked based on the following two SpamRegex's:
<SpamRegex pattern="texas hold[ ]?em" matchType="Title" />
<SpamRegex pattern="(poker|casino|blackjack|roulette).*?game" matchType="Title" />
So far nothing unwanted has gotten through. I've also made a small change to the emails that are sent to notify you of the fact that it has blocked spam; the IP address of the source of the spam is now included in the emails.