I’ve had a bit too much weird spam lately, so I’ve added a CAPTCHA system where, if you want to post a comment, you have to recognize and type in two deformed words to prove you’re not a robot. I found this specific system, reCAPTCHA on Lessig’s Blog. Here’s how they describe themselves:
reCAPTCHA asks commenters to read two words from a book. One of these words proves that they are a human, not a computer. The other word is a word that a computer couldn’t read. Because the user is known to be a human, the reading of that word is probably correct. So you don’t get comment spam, and the world gets books digitized. Everybody wins!
Genius! The work of Luis von Ahn continues to make waves.