I have a medium-low traffic blog, but it often becomes the victim of blog spam. In the past, I turned off the blog ping-back to stop the automatic spam first. Then I added Miguel Jimenez's free Clearscreen SharpHIP CAPTCHA control that I saw in use on Scott On Writing. I use the same .text blog engine as Scott Mitchell so I often visit his site when I encounter problems.

The CAPTCHA control stopped all the automatic spam but it did not stop the manual spam. Spammers can hire cheap labor from third-world county to spam manually. I still got in average 3 spams each day. It still becomes a hassle to delete them if I do not clean them up for a while. Scott simply turned off the comment support when he is going away. I decide to write a validator control to stop the spam.

The idea is to stop the spam at its cause. The economic reason behind the blog spam is to generate links to other sites so that Google will rank those sites higher. So a blog spam always contain a large number of links. Since a normal blog comment seldom needs more than a few links, a way to stop the spam is to detect the number of links in a comment. If the number of links is beyond a threshold, the validator control will stop them. I spent a few hours to implement the control. I have not seen a single spam since them. For now, the spammer are looking for easier targets.

I will publish my control in near future to be used by the community.