Mollom.com - Fight Spam, Save Ham

Mollom is a new web service that helps you protect the integrity of user-generated content on your site by blocking or filtering out spam with an innovative system. Instead of simply classifying user-added content as ‘spam’ or ‘ham,’ Mollom adds a third ‘unsure’ category. Messages determined to be spam are automatically discarded, ham messages automatically make it through, and only those messages classified as ‘unsure’ are presented with a CAPTCHA challenge to confirm that the user adding the content is human. Of course, like any program, Mollom can make mistakes. But if a spam message ever does make it through, the user should report it and Mollom is designed to learn from its mistakes, constantly increasing accuracy over time. According to Mollom.com, currently 99.4% of messages classified as ham are done so accurately.

"Mollom is not just your average spam-fighting service. It is based on a radically new approach that both improves its spam fighting precision over time and reduces the moderation effort needed to correct its mistakes".

By using Mollom, sites could choose to allow anonymous users to post, with less worry about spam messages coming through. Allowing users to post without going through a registration process is a good way to increase participation. And during its Beta release, Mollom is a free service - which will certainly encourage people to give it a try, and this could create willing paid subscribers in the future.

How does Mollom’s accuracy compare to that of significant competitors like Akismet and Defensio? Are the results of its unique ham/spam/unsure system of classifying user-added content significant enough to set it apart from similar tools that have been around for longer?