Slashdot Mirror
Google Using ReCAPTCHA To Decode Street Addresses
smolloy writes "Apparently some users of reCAPTCHA have recently begun seeing photographs appear in their CAPTCHA puzzles — photos that look very much like zoomed in house numbers taken from Google Streetview. It appears that Google has decided to put the reCAPTCHA system to help clean up Google streetview images, and 'according to a Google spokesperson, the system isn't limited to street addresses, but also involves street names and even traffic signs.' A large collection of these has appeared on the Blackhatworld website."
And put your house number in Roman Numerals. Nothing like living in number CLXXIV to screw up the recaptcha. Anyone answering with 174 is likely counted as wrong...
Those who can make you believe absurdities can make you commit atrocities. - Voltaire
Yet Google would have to know what the address numbers really was in order to validate the reCAPTCHA, so that can hardly be why they are doing it. They don't need to crowd source an answer that they already know.
No they don't. They also add an altered text image alongside the picture (which presumably they generated), and can use that to validate the CAPTCHA. The street number can be validated by numerical probability (if 70% of them say it is "257", and the numbers "2,5,7" appear frequently in the rest, it is probably "257") even if they don't already know what it is.
"None can love freedom heartily, but good men; the rest love not freedom, but license." --John Milton
I don't think you know how reCAPTCHA works. You are always presented with two different items to decode. One of them is always a known answer, and the other they are less sure about, but become more sure after they show it to enough people and get a crowd sourced answer. They don't give you two prompts just to be double sure you are human.