WP Spam Fighter free WordPress plugin

This plugins prevents comment spam without requiring you to moderate all comments or your users to use user-unfriendly captchas or answer stupid arithmetic questions. It works using two methods (which can be combined). It boils down to the following behavioral patterns normal comment authors (not spammers) will have: Normal users actually do read your post, which takes time. So someone sending a comment only a few seconds after having loaded the post has to be a spammer. Normal users do not fill fields which are not visible. The first mechanism basically notes down when the page was loaded and when the comment was posted. When the comment is posted, if the timestamps are missing or if the user didn’t spend enough time on the page, the comment posting will fail. The great thing about this approach is that it not only stops bots but also human spammers. The second mechanism based on a hidden field not being filled is what’s usually called a honeypot-based mechanism. Spam bots will usually go through all fields in the form and try to put in some value. Normal users won’t do that since they cannot see the fields. Note that this plugin can be used in addition to other plugins using different spam detection mechanism e.g. Akismet.