Plugin Review: WP Mollom

March 15th, 2009
Weekly Plugin Review, WordPress Plugins

We hate spam. We hate it so much that we always find solutions to spam. So, this week we continue our Weekly Plugin Review series with a review of an Akismet alternative called Mollom.


This plugin makes it possible to use the anti-spam services provided by Mollom on your own WordPress blog. What is Mollom? It’s a free anti-spam service that was founded by Dries Buytaert (Drupal) and Benjamin Schrauwen. The plugin can be used as a substitute for Akismet, Defensio, Spam Karma and others.

What does it do?

Mollom works much like Akismet: comments are sent to a central server which uses intelligent, self-learning algorithms to determine wether or not a comment is spam or not. Spam-classification isn’t a binary process and as a result, common anti-spam services perform bad when handling false positives. Mollom takes care of this. If it can’t clearly classify a comment, it will present the commenter with a secure CAPTCHA test instead of dumping the comment on an ever-increasing moderation queue that needs frequent attention. Mollom is a centralized service which can identify spammers across the network of websites who use Mollom. When a single spam-source is identified on one or more sites, the whole network will be protected against spam from that source.

The main target is to make it as less time/effort consuming to fight spam so that weblog administrators can focus on what really matters: blogging and having fun!


  • Easy install: Install the plugin through WP Extend or through the zip file. Register your site with Mollom to get a set of keys and configure the plugin.
  • Spam blocking: The plugin blocks spam before it’s even saved to the database. Only ham and comments for which a CAPTCHA has been successfully solved, will be saved.
  • Send feedback to Mollom: The plugin provides an alternate moderation module in the admin interface which allows you to send feedback to Mollom if, in your view, a comment is a false positive nonetheless. Mollom learns from this feedback!
  • CAPTCHA: You can see in the moderation queue which comments are ‘unapproved’ or got a CAPTCHA. This should make it easy to spot potential false positives.
  • Statistics: Detailed statistics which show how Mollom is performing on your blog.


Honestly, there is not much I can talk about the effectiveness of the plugin, because testing this requires a few weeks / months before its true results can be seen. However, I am pretty pleased that there is yet another secondary service to Akismet and this one offers a few extra features.

The fallback to the CAPTCHA option is a really good alternative to just blocking the user or the comment landing in the moderation queue and you requiring to manually approve comments.

Mollom is available completely for free with upto 100 successful captcha and 100 legitimate posts, i.e. comments, posts, forum topics etc. per day. If you’re site is any heavier than this, then you’ll need to upgrade to the paid option of Mollum with is 30EUR monthly.

If you’re getting started on the plugin you can refer to the manual for help.

Now, it’s your turn to Review:

We published a list of reviews from our readers today. I’m pleased to have received eight entries in less than four days. This week you have a choice of six plugins to choose from:

You have until Saturday, March 21 – 11.59pm EST to send in your review to submissions AT wltc DOT net with the following information:

Subject line of the email: [APAD Plugin Review]: plugin name. Replace plugin name with the name of the plugin you reviewed.

Content of the Email:

  1. URL of the review on your blog. Make sure this is a direct link to the post
  2. An excerpt of your post. Maximum 50 words. This will be used by us.

Remember you’ll need to link to the corresponding review on our blog when you’re reviewing a plugin. You do not need to review a single plugin. If you so choose, you can review all the six plugins above in individual posts and send us separate emails for each of them! Refer to the original post for more details.




  1. Rofikul Islam Shahin (1 comments.) says:

    “…that there is yet another secondary service to Akismet and this one offers a few extra features.”

    I guess I’m gonna try it out, of course, testing this kinda stuff are pretty time consuming, but Askimet’s been catching some good comments on my blog, I was kinda looking for something like this.


  2. Joachim (4 comments.) says:

    Looks good to me! I will check it out!

    So long

  3. George Serradinho (107 comments.) says:

    I can understand why so many people are developing their own spam plugins.

    It would be nice if you could get one plugin that had most of the options. I do understand that there is Askimet, but it does not catch all and sometimes catches comments and marks them as spam.

  4. Danny Brown (2 comments.) says:

    Have to wonder about the usefulness of a spam plug-in that still utilizes Captcha. This is one of the features that most blog commenters are complaining about and often deters comments from being left.

    • Matthias (2 comments.) says:

      The point of Mollom is *not* to rely entirely on CAPTCHA’s to block spam.

      The idea is that CAPTCHA’s are used to help the system learn how it can differentiate between spam and ham.

      This means that:

      1/ a commenter will only see a CAPTCHA if Mollom is unsure about the spaminess of a comment.
      2/ Mollom is a neural network. More registered blogs will give it more feedback to finetune it’s ability to detect spam.
      3/ This would mean less CAPTCHA’s when the system get’s better at sniffing out spam.

      Statistics on my own blog tell me that regular commenters that are known by the Mollom network are never or rarely confronted with a CAPTCHA and over time, the amount of CAPTCHA’s that were shown decreases. The same would stand on other Mollom protected blogs.

  5. Rui (1 comments.) says:

    Have a try, thx~

  6. Hikari (79 comments.) says:

    Very nice initiative, we need more plugin reviews! :D


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