As if we needed any more proof that CAPTCHAs don't always work, it seems that spammers have now successfully cracked the GMail CAPTCHA. A one-in-five success rate is being reported, and it appears that there are multiple bot-nets taking a tag-team approach in hacking the sign up process. This is particularly dangerous, since Google's domains are highly unlikely to be blocked by any website or ISP.
I don't know what the solution to this problem is (if I did I'd be rich), but hopefully Google will figure out a way to prevent this kind of nefarious activity from continuing to happen.