I like taking a look at what's coming out of the Microsoft Research Labs (MSR) and came across a useful little feature recently that I thought worth sharing. Unless everyone already knows about it and I'm the last one...always a possibility.
It's the equivalent of a so-called CAPTCHA (see http://www.captcha.net/) that we've all come across many times: it's a way to prove you're a human being and not a computer.
I actually find CAPTCHA's pretty tricky sometimes and have failed the test on a number of occasions. So I was interested to see that MSR have a different approach - it asks you to identify species of animals from a series of photos. For a human this is extremely simple, but for a computer it's all but impossible to do.
Take a look at http://research.microsoft.com/asirra/. You can hook it into your website pretty easily and free of charge. Oh, and I haven't failed the test yet!