Top Six Drupal Modules to Prevent Spam - devshed. There are some wonderful Drupal modules that can help your site in its quest to fight spam. If you are looking to protect your email addresses from harvesting or just want to eliminate spammy posts and comments, this list is for you. Here are six of the top Drupal modules for spam prevention. Mollom Mollom is what is referred to as an “intelligent” web service. Mollom basically splits content into two categories: ham or spam. If Mollom is unsure if content is spam, it will go to a secondary line of defense – the CAPTCHA challenge. Link: reCAPTCHA The reCAPTCHA module is rather simple in its form but highly effective. CAPTCHA integration works well in various situations, making it an attractive service for a wide range of sites.