CAPTCHAs as we know them are mostly a text based tool. You get some distorted words, letters or numbers, and you retype them in order to prove you’re human and not a spam bot.
But is the era of text based CAPTCHA coming to an end?
According to David Bradley of sceincetext.com, it is indeed a possibility. [...]

As you may already know by now, Captcha is a common approach to prevent access of users that aren’t human to all kinds of websites. The captcha is a kind of test that requires verification of distorted image plus textual content which is deciphered easily by humans but not by computer bots. 
However, it appears that [...]