Important notice for Drupal 5 Mollom users

Earlier today, we fixed a significant bug in the Drupal 5 module for Mollom that was the likely root cause for some problems reported by several of our Drupal 5 Mollom users. In some cases, the list of available Mollom servers was not being reset correctly, leaving Mollom with an inaccurate list of servers to contact to validate CAPTCHA responses or to analyze comments. If you received some errors about Mollom servers being unreachable, or if you noticed spam getting through to your site, read on.

A bug fix release of the Drupal 5 was made available today: if you are using Drupal 5, you should upgrade to the latest Drupal 5 release available from As an interim fix until you have time to upgrade your Mollom module, you can force your server list to reset to a correct set of values by visiting the Mollom settings page (?q=admin/settings/mollom or admin/settings/mollom, depending on your Clean URLs setting).

Note that this bug only affected the Drupal 5 version of the Mollom module. The latest version of the Drupal 6 Mollom module does not have this bug, although if you are not running the latest version of the Drupal 6 Mollom module, we certainly encourage you to upgrade. As you can see on, too many people are still using outdated versions of the Mollom module for Drupal.

We apologize for this bug, and for any difficulties it caused any of your users. At Mollom, we're committed to a seamless experience that keeps you from even thinking about spam on your site. While we may not be there yet, we're fast working toward that goal.

Thank you for using Mollom, and please feel free to contact us if you have any additional questions or concerns.

An [unsolicited] review of Mollom's CAPTCHA service

As one of the team that routinely responds to support requests for, I've seen a lot of questions come through our queue. Especially as we grow the Mollom infrastructure in response to changing spam patterns across the web, lately we've had more than our regular number of support challenges. Fortunately, with the infrastructure, hardware, and algorithmic improvements Ben and Dries have implemented, we're back down to our usual level of support requests.

The thing about a support queue is -- of course -- you're usually talking to people with questions, or assisting with a particular problem. There are tons of Mollom users out there who never write us for support because, we hope, Mollom just works for them. Those are users' we'd like to hear from more, because their feedback and thoughts are invaluable.

Dries pointed out just such a post by Alvin Alexander to me today. It's on, which uses Mollom to protect its comment and contact forms from spam. This is how the article sums up Mollom:

"Wow, it's rare for me to say this about any piece of software, but I don't have any complaints about Mollom. It was a breeze to set up, and I rarely even think about it ... as far as using it with Drupal is concerned, it just works."

I'd encourage anyone considering using Mollom to read his post. It's a great tutorial, and really hits all the high points of Mollom's feature set. I know I'll be referring people to it in the support queue so its going on my list of bookmarks.

Thanks, Alvin! We appreciate the feedback, and we're glad that Mollom is working out so well for your site!

Mollom for Laconica

Laconica, billed as an open-source microblogging tool similar to Twitter or Jaiku, now has its own Mollom plugin to reduce comment and posting spam. Laconica is designed to allow people in a community, company or group to exchange short messages of 140 characters or less, over the web. The Mollom plugin for Laconica is available at, and is written in PHP.

IIS module for Mollom

Zion Security, a Belgium-based company specializing in the security analysis of web sites and systems, has used Mollom's open API to develop a Microsoft IIS module utilizing Mollom to detect and prevent comment and posting spam.

This module is unique in that it is a HTTP module coded for Microsoft IIS, comparable to an Apache module, and allows Mollom to potentially expand to a number of ASP/IIS based systems.

The Mollom IIS module is available as a zipped file for download here and is listed on our downloads page. It checks any submitted form for spam using Mollom's spam detection analysis, and like other Mollom plugins, requires you to obtain a set of registration keys from before it can be actively used to protect your ASP-based forms.

Because it is written as a module at the webserver layer, it may be possible to use Mollom's spam-detection and CAPTCHA challenge ability with existing web applications running on IIS (think SharePoint or DotNetNuke). It's an interesting approach and one we haven't really considered ourselves. It will be interesting to see how this develops, and if it sticks.

Hundred million spam attempts blocked

At Mollom, our spam-filtering startup targeted toward eliminating comment and post spam, we've just reached two important milestones: we blocked our 100,000,000th spam message, and we're now actively protecting over 10,000 websites.

It was only about three months ago that we celebrated our 50 million message milestone, and two months before that we reached twenty-five million. These milestones are coming fast now. Will we double again in the next three months? Only time will tell.

In fact, these statistics are for our public servers only, and don't include message processing on private servers we operate on behalf of our larger clients. Mollom filters about an additional 4 million messages each day for Netlog, for instance.

All things combined, we're processing up to 150 million messages a month! Since it can take multiple HTTP requests to process a single message, we're handling well over 200 million HTTP requests per month.

We're currently working on some important architectural changes to the Mollom backend to allow it to learn faster while making it easier for us to debug, analyze and oversee its actions. We're also busy upgrading our infrastructure to cope with our growth. It is a work in process, but once completed, it should allow us to focus more on improving the effectiveness of our classifiers and adding new features.

One thing is for sure though -- we're going to keep doing what we're doing, and if you're a Mollom user, we're glad to have you along for the ride.