I’ve been having a problem with comment spam lately — spammers using the blog’s comment functionality to post links which will get indexed by google and artificially boost their page-rank.
A) Google has announced, with support from MSN and Yahoo, rel=”nofollow” which should lower the incentive for spammers using this technique. The .TEXT version requires a recompile at the moment and I’m not running the source based install, so I’ll have to wait a while before implementing this.
B) A HIP-CAPTCHA Control can be added to .TEXT to make it v.difficult for spammers to automate posting. Clearscreen SharpHIP. I have chosen to skip this technique for now.
C) Preventing .Text blog spam using triggers. This is what I’ve gone with so far. Since all this blog content goes into a SQL Server 2000 DB, it is easy enough to add a trigger which checks for known spam titles and a high occurrence of HTTP in the comment data. Many thanks to Chrissy LeMaire for the code. Now that I look, it seems she is ALL-OVER this problem. Please email me separately if you post a comment that gets eaten by this filter accidentally. I’m terrified of false positives while spam filtering. Which is why I use Cloudmark SafetyBar (no false positives) for mail BTW.