PWNtcha captcha decoder

One site that's been getting a lot of attention of late is PWNtcha, a project which is demonstrating the inefficiency of many of the CAPTCHA systems designed to verify human identity. CAPTCHA is still, of course, a useful tool, but it's important to be aware of potential weaknesses.

CAPTCHA is just one of the techniques we covered in our Six Apart Guide to Comment Spam, and can be a good choice in conjunction with other spam-fighting options.