Comment spam is a problem that hits many blog systems, but fortunately on WordPress there are some very robust ways to deal with this scourge. We’re building some important protections into 1.3 but in the meantime you should take action to protect yourself. Our own Podz has put together a great resource on the Codex on how to Combat Comment Spam that has dozens of excellent methods, and here are some of the highlights:
Spaminator
Kitten’s Spaminator has protections against floods of comments and assigns score values to different characteristics of comments. It also has code included to give a delayed response to known spammers, which slows down their bot networks.
Spam Karma
Dr Dave’s Spam Karma takes a multi-faceted approach that uses literally dozens of characteristics of the comment, from the age of the post to how quickly the comment was posted, to decide a score or “karma” for a comment, much like the Spaminator. It also allows people to increase the karma of their comment if they’re on the edge by verifying an image or an email.
Stay up to date
Again these are just two of dozens of plugins available, so watch the Combat Comment Spam page and the WordPress Planet for the latest and greatest. You can also read Jay Allen’s Comment Spam Clearinghouse blog for some background of the comment spam fight and his efforts on the Movable Type side of things.