One way to get rid of spam comments is to install a comment and trackback spam blocking plugin. These are the comment spam block plugins that are available for bloggers using Movable Type and WordPress:
 

For Movable Type weblogs, the most popular plugin is MT-Blacklist by Jay Allen. This plugin helps you to get rid of comment and trackback spam for Movable Type version 1.6.5 or higher. If you have MT3.1x, this is already included in the plugin pack.
 

For WordPress weblogs, one of the plugins to use is WPBlacklist by Fahim Farook. This plugin works in WordPress version 1.2. It is included in the WordPress plugin pack and it just needs to be activated.
 

To activate this plugin, go to the 'Plugins' section of your weblog's WordPress administrative controls. As of this writing, the latest version is WPBlacklist 2.6.1.
 

Another WordPress comment spam blocking plugin is called Three Strikes You're Out by Mark Ghosh and it uses a point system to eliminate spam. Just copy the plugin, upload the file in to your wp-content/plugins directory, then activate it in your WordPress weblog

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