How do you let people create user accounts or post comments on your Web site without letting spam bots in? Simple — make your users prove they’re human. Many Web sites use CAPTCHA (Completely ...

Facebook is running tests of a new CAPTCHA system that requires users to upload a clear photo of their face to prove the account is not fake and belongs to a new person. The new tests were spotted ...

It’s not as if it hasn’t been done before, but researchers at Stanford quantified ways to crack the CAPTCHA test many web sites use to make users prove they’re human, and recommended ways to make sure ...