Neat and I really like to see innovation in this area. Although I think because outsourcing captcha to humans is so cheap, methods like this are not going to w

Neat and I really like to see innovation in this area. Although I think because outsourcing captcha to humans is so cheap, methods like this are not going to win in the long run. I think a more sustainable strategy is to make it more and more expensive for those who want to solve captchas in large volumes. Things like solving a cryptographic challenge using the computing power of your machine. i.e. making it cheap/easy enough for legitimate users who may need to submit the form once a month but such that it becomes too expensive for those who want to exploit it and solve 100 of them in 5 minutes.