Further fodder for criticizing conventional CAPTCHAS [fffccc]: The cybersecurity company MessageLabs released a report on spamming. There seems to have a significant rise in spam activity coming from Gmail accounts during the last month. Considering that spammers need a success-rate of 20 - 30 percent to operate, it's plausible to assume that some of them have started breaking Google CAPTCHAS automatically. That's still not a proof, though I'm confident it will be coming relatively soon.