The old ones where you had two words to guess. One of them was from a scan from their big book project that the computer couldn’t work out.
The system has been reported as displaying over 100 million CAPTCHAs every day
Some have criticized Google for using reCAPTCHA as a source of unpaid labor.
[29] They say Google is unfairly using people around the world to help it transcribe books, addresses, and newspapers, and label image data for its driverless car effort without any compensation.
[30]In response to this criticism, competitors have emerged promising unique value propositions like compensating the website host or end-user for the work they do.
[31]
The use of reCAPTCHA has been labelled "a serious barrier to internet use" for people with sight problems or disabilities such as dyslexia by BBC journalist Stephanie Hegarty.
[32]
