Asirra or Captcha?

I've just heard about "Asirra" and tried it. But, I am a little bit confusing about using. What is your choice for usability?

Asirra or CAPTCHA, and why?

Answer

CAPTCHA is Completely Automated Public Turing test to tell Computers and Humans Apart. So, indeed, Asirra is (a type of) CAPTCHA... If you mean the warped text type of it, I think Asirra is not useful because:

• it requires more time than warped text


• it requires specific interest while trying to fit in a design

I think best type/way is reCaptcha.