Garbled text and kittens: how to prove you're human

Garbled text and kittens: how to prove you're human

Have you heard of a CAPTCHA? Even if you haven't come across the name before, you've still probably used one. CAPTCHAs are those distorted pieces of text you're sometimes asked to type in when you sign up to a website:

CAPTCHAs are meant to be easy for people to solve, but hard for computers to interpret. They help stop automated "bots" from misusing a website's services - for instance, by creating nonsense user accounts or posting spam comments.

The vast majority of CAPTCHAs are like the one shown. They ask you to copy wobbly text into a box. If what you type matches what's shown, you pass and the website assumes you're a real-life person.

There are problems with these CAPTCHAs: even though they're supposed to be easy for humans to understand, in practice they can be devilishly hard to solve. Plenty of sites will attest to that. They also create all sorts of usability problems - and it's not like they're impervious to hackers either.

Given these issues, it's no surprise that some websites are finding more inventive ways of getting people to prove they're human. Some are easy-to-use. Some are probably easy-to-hack. But all offer a break from the traditional text CAPTCHA. Done well, they can even form a part of a website's personality and branding.

Here are four I've come across lately. If you need to make sure real people are signing up to your own website, maybe you could take inspiration from one of them.

1. Choose the matching object

When you sign up to social networking site YUNiTi, you'll be asked to pick three matching 3D images from a selection. This system relies on our ability (and a computer's inability) to recognise the same items from different angles.

2. Connect to Facebook

StumbleUpon is an interesting way to find new, interesting websites. And it gets round the CAPTCHA problem in an unusual way, by requesting access to your Facebook account in order to prove you're real.Have you heard of a CAPTCHA? Even if you haven't come across the name before, you've still probably used one. CAPTCHAs are those distorted pieces of text you're sometimes asked to type in when you sign up to a website:

CAPTCHAs are meant to be easy for people to solve, but hard for computers to interpret. They help stop automated "bots" from misusing a website's services - for instance, by creating nonsense user accounts or posting spam comments.

The vast majority of CAPTCHAs are like the one shown. They ask you to copy wobbly text into a box. If what you type matches what's shown, you pass and the website assumes you're a real-life person.