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.