Our Wordpress profanity filter was rated the best profanity filter by WPExplorer.com
Movable Type Profanity Filter Plugin
Filters user comments for profanity using the WebPurify Web Service before they are inserted into the database. Replaces each letter of profane words with a “*”. You need to have a license key to make use of the WebPurify Web Service. We use these keys to track API usage and to identify your custom filters. Once you purchase a key, you will be able to create custom “blacklists” and “whitelists” in addition to managing your keys.