Captchas cracked

Generally the safest way to ensure real humans enter data are so called captchas (Completely Automated Public Turing-Test to tell Computers and Humans Apart – distorted pictures with words in them you are asked to read and type in). Now, these are not only an accessibility issue (how would a blind user type them in?), but clever spammers found a way around them, using free porn and gullible people.