The website planetOzh has an excellent post about blog posts that attract spam.
In it, he provides not only a piece of SQL that you can run to see how your site is affected, but even provided a PHP script that you can upload to your website to graph the results. Mine is to the right. I have my spam cleared out quite regularly, so the results are only recent ones.
As you can see, one of my posts was generating nearly 47% of all the spam. This is usually due to keywords within the article – the fact that it’s about a forum is possible a key. The second place “magnet” is a my review of a Microsoft keyboard. I have no idea why, maybe because of it being Microsoft related.
I’ve resolved the first post by simply closing off comments (it was an old post and I think everything that needs to be said has been). The review, well, I’m not sure what to do there. I want to keep comments open on reviews. Others are mainly WordPress pages, which I need comments available for feedback and support. However, the fact that the plugins are related to PayPal, Facebook, AdSense, etc, I’m sure is no coincidence, and probably help to attract the spam.
So, not a huge amount I can do (having said that, I’ve reduced my potential spam input by 47% – assuming they don’t just target another one of my posts!), but interesting to know none-the-less.
Having said that, I’ve never really thought about closing comments on posts before and it’s something I will do in future – especially when I announce new or changed plugins, as comments can be placed on the main page itself.
Update: A WordPress plugin has been released of the code to produce the spam charts.