That's probably referring to reCAPTCHA, or one of the newer CAPTCHA derivatives such as duolingo. The original CAPTCHA was just a means of increasing defense in the escalating arms race between bots and those who wanted to avoid them.
Dave
In reply to Re^3: solve reCAPTCHA
by davido
in thread solve reCAPTCHA
by quentin
| For: | Use: | ||
| & | & | ||
| < | < | ||
| > | > | ||
| [ | [ | ||
| ] | ] |