Ever wonder how we control spam on Small Farm Central sites? We use a system that you have seen many times throughout the web called CAPTCHA (which stands for Completely Automated Public Turing Test to Tell Computers and Humans Apart).

This is a series of distorted letters and words that is difficult (or hopefully impossible) for a computer program to decipher, but is easy for the human brain to translate.

It's not really important for you to understand the specifics except that a CAPTCHA makes sure that a human is at the other end on comment submissions, emails from the website, mailing list submissions, and anywhere else that we take input from the user.

We use a really interesting implementation of the CAPTCHA called reCAPTCHA (starting in fall 2007) from Carnegie Mellon University which is coincidentally just a few miles down the road in the same city that Small Farm Central is based.

Each CAPTCHA word on Small Farm Central sites is scanned in by a project that is seeking to digitize the literary public domain. There are always certain words that the computer cannot understand as they attempt to encode these books, so the reCAPTCHA project takes the collective brain power that was heretofore wasted on CAPTCHAs and puts it to the task of deciphering these words so that these books can be searched and read digitally in the future.

I won't hope to match the reporting skills of the Wall Street Journal, so that covers the basics: read this Wall Street Journal article for all the interesting details! Thanks, Patrick for the link.

If you want to test a reCAPTCHA for yourself, you are welcome to try leaving a comment on this very entry.