It took me hours to delete all the comment spam that flooded this blog a few weeks back. The experience led me to switch from pMachine, the software I was using, to Expression Engine. Both are produced by the same company, but Expression Engine includes CAPTCHA, a tool that requires anybody submitting a comment to retype a word produced as a graphic image. The idea is that a machine flooding a blog with spam wouldn’t be able to read the graphic and would thus be denied the ability to post. So far it’s working.

CAPTCHA is just one of the topics covered in a comprehensive “Guide to Comment Spam,” just released by Six Apart, the company that owns TypePad. The document clearly is aimed at TypePad customers and at converting those who aren’t (it points out a few drawbacks to CAPTCHA, for example). But it’s still a useful overview of a growing problem.

Thanks to Business Blog Consulting for the link.