Based on Bad Behavior from http://bad-behavior.ioerror.us/ rebuild for full integration into Magento 1.4 and up
== Description of Bad Behavior ==
Welcome to a whole new way of keeping your blog, forum, guestbook, wiki or content management system free of link spam. Bad Behavior is a PHP-based solution for blocking link spam and the robots which deliver it.
Thousands of sites large and small, like SourceForge, GNOME, the U.S. Department of Education, and many more, trust Bad Behavior to help reduce incoming link spam and malicious activity.
Bad Behavior complements other link spam solutions by acting as a gatekeeper, preventing spammers from ever delivering their junk, and in many cases, from ever reading your site in the first place. This keeps your site's load down, makes your site logs cleaner, and can help prevent denial of service conditions caused by spammers.
Bad Behavior also transcends other link spam solutions by working in a completely different, unique way. Instead of merely looking at the content of potential spam, Bad Behavior analyzes the delivery method as well as the software the spammer is using. In this way, Bad Behavior can stop spam attacks even when nobody has ever seen the particular spam before.
Bad Behavior is designed to work alongside existing spam prevention services to increase their effectiveness and efficiency. Whenever possible, you should run it in combination with a more traditional spam prevention service.
Bad Behavior works on, or can be adapted to, virtually any PHP-based Web software package. Bad Behavior is available natively for WordPress, MediaWiki, Drupal, ExpressionEngine, and LifeType, and people have successfully made it work with Movable Type, phpBB, and many other packages.
Installing and configuring Bad Behavior on most platforms is simple and takes only a few minutes. In most cases, no configuration at all is needed. Simply turn it on and stop worrying about spam!
The core of Bad Behavior is free software released under the GNU Lesser General Public License, version 3, or at your option, any later version.
== Magento Interface ==
TODO: rebuild the code to work with Magento in mind.