Mollom

Mollom is an "intelligent" content moderation web service. By monitoring content activity on all sites in the Mollom network, Mollom is in a unique position to determine if a post is potentially spam; not only based on the posted content, but also on the past activity and reputation of the poster. In short, Mollom handles incoming posts intelligently, in much the same way a human moderator decides what posts are acceptable. Therefore, Mollom enables you to allow anonymous users to post comments and other content on your site.

How it works

Mollom may block a post outright if it is from a known spammer. If Mollom is unsure how to classify a post, it may require the completion of a CAPTCHA to accept the post. Posts that do not match a "spammy" text pattern and do not originate from known spammers are accepted without the need to complete a CAPTCHA. Essentially, Mollom acts as a proactive content moderator that is on the job 24 hours a day, 7 days a week.

A stand-alone CAPTCHA solution, which neither considers user behavior nor point of origin, can never achieve this level of informed protection, and generally requires users to solve a CAPTCHA on every post. Using Mollom's text analysis, users must only solve CAPTCHAs when Mollom is unsure about a post.

The Mollom module allows other modules to integrate their forms with Mollom. Forms exposed by Drupal core, including the user registration and comment forms, are supported by default.

Mollom is actively developed and maintained by Dries Buytaert, the founder and project lead of Drupal, and Benjamin Schrauwen. Mollom is currently used by more than 30,000 sites, including Sony, Adobe, LinuxJournal, Warner Bros Records, Netlog, NBC, and others. As of September, 2010, Mollom currently protects over 30,000 websites with an average efficiency rate of 99.93% - which means that only 7 in 10,000 spam messages are not routinely caught by Mollom's filters. Since Mollom began operating, it has prevented almost 300 million spam posts from littering the web.