I now think it is more human than bot after reading the article at www.deathbycaptcha.com. The question actually is how does someone find so many message boards to spam?
The answer is you use the keyword C A P T C H A in a search engine and there are message boards galore! So the method of protection is actually the fatal flaw. How else could they find such a small community like Theremin World tucked away in Kansas with Dorothy and Todo?
The word itself or others common to message boards is a welcome mat! LOL
Purge the entire data base of that nasty word so you are not captured by 21st Century warfare.
Christopher
Death by Captcha_ offers an outstanding low price of $1.39 for 1000 decoded CAPTCHA_.