Captcha

Luis von Ahn is one clever guy. I have no idea if he's smart in the computer science way, but he's clever.

He's a computer science professor at CMU, and his biggest idea is using humans as computers, that is, using humans to do things that computers have a hard time doing. He is most noted for captchas, which are those distorted text you enter to be sure you're a person, and not a bot.

The next new clever idea based on captchas is to digitize text from books that have been scanned in. Facebook has used this, where you type in two words. One word, they already know what it says. The other, they aren't so sure. The word they know is used to make sure that you, the person, is real, and if you enter that word correctly, it's felt that the other word should also be entered correctly too.

In addition to captchas, people can tag photos with relevant words. So the idea is that object recognition is hard in photos, but people can handle it easily. But you don't completely trust the people tagging, so you find a way to prevent the occasionally person who is trying to use bad tags.

Next time you enter a captcha, you may be helping a digitizing effort.