[Finn]

Quote:

Originally Posted by Mauzen Simple questions can be a lot more tricky to solve for bots. They need a quite complex AI just to figure out the intention of the question, and eventually a lot of knowledge of the topic of the website or general stuff. So a bot solving (well chosen) questions has to be really clever, a recaptcha bot just needs a good algorithm (sure there are some AI techniques for image recognition, but thats a completely different kind of AI).

This. I'd imagine an easy riddle with some clever meaning might be the easiest way to filter out the bots.