By the way, picking one token from the captcha and returning it beats the captcha 7% of the time, if the examples are representative. Spammer wins, since he can generate requests by the hundreds of thousands.
> The 1st number from 25, eight, 6, six and 27 is?
So is the answer 25 or 6?
I've come to the realization that CAPTCHAs aren't the solution, or at least can't be a standalone solution. Make the CAPTCHA easy enough for a human to not be blocked (pick the cat from these 3 photos) and the bot still wins 33% of the time. Make it hard enough that the user has to invest energy to 'solve' the problem in front of them and you alienate users by treating them like criminals.
Interpretation 2: It's a numerical list of numbers, numbers being ordered by value have an implicit sort applied to them, pick the first element in that sequence = 6.
#2 is a very programmer thing to do ;)
Think about it: the actual problem with spammers defeating CAPTCHAs is low quality content. I'd much prefer to expend energy trying to stop low quality content, which is often delivered by non-spammers :)
I wrote a blog post expanding on these ideas: http://cmurphycode.posterous.com/the-problem-with-captcha
Something like ReCaptcha is already for all intents and purposes bot-proof. A text captcha like this looks like a step backward.