I’m loving this new anti-spam implementation (above) I just found at searchmetrics.com. We’ve all seen CAPTCHA, where characters are displayed in ways that make it difficult for computers to read them. And we’ve also seen calculation used as a barrier, where you have to add, subtract, or increment numbers before you can proceed.
But this one combines them. So you have to read the CAPTCHA to get the inputs, and then do a calculation. Very cool. I’d love to see data on spam that gets through this vs. with one of the two techniques alone. ::