everyone's complaining about spammers bypassing even the most advanced and irritating "are you a human" captchas, but i haven't seen anyone discussing this solution. i was watching this documentary last night, i was half asleep so i don't remember much about it. it was narrated by this guy who sounded kinda like indiana jones if he hadn't slept in two days.
anyway in the documentary they used a new kind of captcha called a voight kampff test. they ask you questions about how to keep a pet turtle or something and it can tell whether you're a human or not. it needs webcam access to see your eyes for some reason, but it seemed pretty reliable. it seemed a lot less annoying than selecting all the motorcycles at least