You must have seen such images many times — colorful images with distorted text at the time of signing on some Web registration forms. CAPTCHAs are used by many websites to prevent abuse from non human trials to submit a web form.
reCAPTCHA is a free CAPTCHA service that helps to digitize books, newspapers and old time radio shows.
About 200 million CAPTCHAs are solved by humans around the world every day. In each case, just a few seconds of human time are being spent. Individually, that’s not a lot of time, but in aggregate these little puzzles consume more than 150,000 hours of work each day. What if we could make positive use of this human effort? reCAPTCHA does exactly that by channeling the effort spent solving CAPTCHAs online into “reading” books.
If you want to put a reCAPTCHA on to your site , sign up here.
Now you must be wondering if CAPTCHA is an acronym. Yes it is. Completely Automated Turing Test To Tell Computers and Humans Apart. I know P is missing.