You ever see one of those bot fooling thingies and kind of wish you could get one for your site? at reCaptcha.net, you can get that service for free!
Further, as shown on Wired Science, the word scans are used to verify the words in books that are being digitized. I don't think it's going to get a lot of use at my sites, but it does offer another hurdle of difficulty for spambots.
