Our earlier conversation on CAPTCHAs

Just found this: Negative Captcha.

It talks about making the whole process more convenient for the people you want to let it, instead of the bots. You hide a field via CSS from the user, and when it is filled in, a script on the backend keeps the bot out.

Interesting

Definitely an interesting idea. It's got it's faults, but I'm not sure they are any worse than the once that a normal CAPTCHA has. Do you plan on implementing this idea?

Possibly

I haven't decided. I am trying to find more people that use it to see its pros and cons and how effective it is.

I'll keep you posted.