What about a security pattern recognition (something like letters and numbers) test whenever you want to create a new thread?
I've seen that on other forums, and it is really annoying. Even if they limit it to the first 5-10 posts you make, it's still really annoying. Especially when the CAPTCHAs are hard (or sometimes impossible) to read. I agree with EinTroll, no need to annoy legitimate posters. There are better methods of spambot control.
