i'm not sure what the current state of the art is, but my favourite way of solving captchas was the porn vendors who were monetizing their sites by presenting c

i'm not sure what the current state of the art is, but my favourite way of solving captchas was the porn vendors who were monetizing their sites by presenting captchas in front of their videos, but the captchas were captured from legitimate sites. so every time a person solved a captcha to watch a video, it enabled a bot to access a captcha-protected resource.