Comment spam is becoming more and more a problem each day. Fortunately there is a way to deal with this. Jay Allen has written a Movable Type plugin called MT-Blacklist. This plugin will block new incoming spam and clean existing spam in comments. He is also maintaining a constantly updated spam database, called the Comment Spam Clearinghouse, for use in identifying comment spam. Anyone who ends up using MT-Blacklist should submit new spam to the clearinghouse to increase the quality of the list. Once MT-Blacklist is installed a great way to stay up to date with new spams is to subscribe to the Blacklist changes RSS feed. The clearinghouse is not specific to Movable Type, it can be used by any weblog software, someone just has to write the plugin.