But serious spammers would prefer to spend this time writing a bot capable of spamming all forums based on some widely used engine.
Cracking this captcha won't give you access to any significant audience.
Cracking this captcha won't give you access to any significant audience.
If every forum had a completely different captcha system, forum spam would pretty much die out.
The problem is to design a CAPTCHA that implements just enough headache to make it worthwhile not to overcome and at the same time not frustrating users. I think this chess problem uniquely and elegantly solves the problem for the site in question by achieving both.
Then again, I am not familiar with the users, maybe the site is often trolled by chess mastah wanna-bes.
http://www.codinghorror.com/blog/2008/03/captcha-is-dead-lon...