My afternoon has been spent trying to stop spam in Biblio.com’s forums. Stopping spam is usually a thankless job. Today it was fun.

ReCAPTCHA is an interesting take on proving you are human. It displays two words from pages that could not be OCR’d. One word is known and the other is not. Each user enters both words, if the known word is correct the user is approved. Additionally the unknown word has a good chance of being correct. Once several people have agreed on the unknown word you can have confidence that it is correct.

The reCAPTCHA system makes proving you are human of benefit, currently they are using pages from the Internet Archive and old editions of the New York times.  For me, it made my day a little more interesting. I hope that use of the reCAPTCHA system catches on, it could make a large number of old documents accessible.