About five years ago, Louis von Ahn was the PhD. student who
came up with the idea for CAPTCHAs, the little requests to "type this" before you could fill out a form or sign up for a service. These days, of course, such CAPTCHAs have become nearly ubiquitous. Since then, Ahn has gone on to create other online systems that figured out ways to shift labor resources to users, such as
the ESP Game, which is designed to make image search much more effective (and which
Google eventually licensed). However, it seems that Ahn has switched his attention back to CAPTCHAs after recognizing what a productivity drain they must be. The nice thing about the ESP Game is the end result benefits image search. CAPTCHAs only help weed out spammers and scammers. However,
John writes in to let us know that Ahn's latest work is
about making CAPTCHAs useful. What he's done is made it so the text that users have to type are scans from books or other printed materials that are being scanned by Brewster Kahle's Internet Archive project. That way, each time people are simply trying to enter a comment on a website, they're also helping to turn a scanned word into text for the Internet Archive. Of course, if someone were really sneaky, they would just do the same sort of thing and hook it up to
Amazon's Mechanical Turk and keep all the earnings. Every time someone entered a comment on a site, it would earn you money. So, if anyone wants to do this, please reserve a cut for me.