Kristyk who turned me onto WordPress (which Knoxjon uses) has an interesting antispam setup for her comments. When commenting, you have to answer a random math question “What is the sum of 9 and 3?” Registered users don’t see the question. Michael Silence gets rid of all comment spam by requiring registration to post a comment. Now, where do you register?
I haven’t had a single spam comment since I started this. Plus, I’ve had a lot more registered users!