Yeah, CAPTCHA codes are easily bypassed by the more sophisticated bots. There's already a CAPTCHA requirement when a new user registers, so clearly the bots that are tormenting this forum are in the "more sophisticated" category. There are alternatives, such as questions which require human answers (like, "What's 1 + 7 - 3 = ?") but even these aren't 100% secure. Technologies like these need to be updated regularly if they are to be effective for more than a few weeks.

Maybe combining several of these technologies would help. For instance, any user with under 10 posts has to enter two or three different codes (of a different nature) for each post they wish to make; after their tenth post the requirement is lifted. Or if you're really desperate, just set it so that any user with less than 5 or 10 posts has to have their posts verified by a mod prior to being published. That way only the mods will be bothered ha!

FUCKING spam.