Gizmodo is reporting that ReCAPTCHA is now using street view address images its spam filter as one of those words you have to put in to verify you're human. Their article quotes Google as saying:
We're currently running an experiment in which characters from Street View images are appearing in CAPTCHAs. We often extract data such as street names and traffic signs from Street View imagery to improve Google Maps with useful information like business addresses and locations. Based on the data and results of these reCaptcha tests, we'll determine if using imagery might also be an effective way to further refine our tools for fighting machine and bot-related abuse online.
Hopefully this means Street View will actually be useful beyond seeing how someone's house looks, or searching for people caught unawares on camera.
This phenomenon was popping up as recently as last weekend for some users:
CAPTCHA stands for Completely Automated Public Turing Test to Tell Computers and Humans Apart. It is a spam filter designed to make sure only humans, not bots or other programs, can make it to certain web pages to leave comments or sign up for certain services. ReCAPTCHA takes words that cannot be read by computers and sticks them in CAPTCHA for a human to decipher. Since Google acquired the service back in 2009, it has already been used to digitize books, newspapers, and old time radio shows.