Mollom CAPTCHA service review

Summary: This is a review of the Mollom CAPTCHA service, based on our experiences using Mollom with Drupal here on the website.

When I switched this website over to Drupal about three weeks ago, I knew I also needed to find a good Drupal CAPTCHA tool to deal with both comment spam (also known as "comment form spam") and contact spam (contact form spam). After digging around a little bit, Mollom seemed like it might be a good tool, especially since both Drupal and Mollom were both created by the same author, Dries Buytaert.

I'm glad to report that almost three weeks after the switch to Drupal, the Mollom CAPTCHA service has been doing a very good job of handling the spam, both comment spam and contact spam. And as a pleasant surprise, it turns out that very few legitimate users ever need to see a Mollom/Drupal CAPTCHA image form. (More on this below.)

So, three weeks into it on a production site -- here's a review of my experience using the Mollom CAPTCHA service.

Mollom CAPTCHA service - background

Mollom is offered as a "CAPTCHA service", meaning that you install a client application (or library) on your website, and this client communicates with the Mollom CAPTCHA service, which is provided in a SaaS (Software as a Service) model.

The Mollom website offers clients for most popular blogging tools, including Drupal, Wordpress, Joomla, and others. There are also developer libraries for all the popular programming languages, including Java, PHP, Ruby, Perl, etc.

Mollom CAPTCHA installation with Drupal

As mentioned, this website runs on Drupal, and installing the Mollom client in Drupal was a breeze, just as described on the Mollom website:

  • Download the Mollom client
  • Create a Mollom account
  • Get your keys, and activate your website

For my Drupal website, I just downloaded the Mollom version for Drupal 6, and installed it just like any other Drupal module.

After that, I created a Mollom account, which requires only very basic information, including your login name, email address, and the website whose comment form and contact form you want to protect.

Mollom CAPTCHA - public and private keys

The main reason for needing a Mollom account is so you can get the public key and private key that Mollom uses during its client/server communications. You can find those keys very easily on the site.

In Drupal adding these keys is very easy. Just go to "admin/settings/mollom", and copy and paste the public and private keys there, and your site should be ready to communicate with the Mollom site.

Mollom CAPTCHA form settings

As you can see from your Mollom CAPTCHA settings form (at least in Drupal), the next thing to do is decide how you want to protect the forms on your website, including the comment form, contact form, user registration form, and others.

The Mollom help text provides some nice suggestions here, and I followed that advice. You can see the Mollom "text analysis" and CAPTCHA image form settings I've chosen in the figure below:

Mollom settings within Drupal

I was pleasantly surprised by the text analysis option. When I first started down this road, I assumed I'd be using CAPTCHA image protection on all my forms, but so far I've been very happy with the combination of text analysis followed by a CAPTCHA image backup, as shown in the settings above.

Mollom CAPTCHA service results

Of course what everyone wants to know is "Does Mollom work?", does it protect your comment form and contact form from spam?

Three weeks into this, and I'll say yes, I've been very pleased with it. But one of the cool things about Mollom is that you can see this yourself, in a simple graph which you can see from both (a) your Drupal admin panel and (b) in your account on the website.

Here's the current Mollom ham and spam graph for this website. As you can see, it shows the total number of comment form attempts, including those Mollom considered "ham", and those it considered "spam":

Spam attempts blocked by Mollom (comment form, contact form)

As you can see, there's a very disturbing trend in the number of spam attempts over the last week, but just as importantly, Mollom has done a great job of not letting the spam get through. (As for that increase, I'll assume that many of the spammers of the world now know that this site runs on Drupal, and that it has comment and contact forms.)

Mollom CAPTCHA - feedback

With Mollom protecting my website forms with its text analysis and CAPTCHA technology, I've had just a few pieces of spam get through. If there's anything nice about this with Mollom, it's that as a site administrator, I can very easily report these spam comments back to the Mollom server.

All I have to do is click a link below the spam comment that's labeled "Mark as abuse", and then select one of the options on this feedback form:

Mollom comment form spam feedback options

I really like this setup. It's simple, but it also lets me categorize spam attempts. That's nice, because there really are different levels of comment spam, and already I've seen at least one spam attempt in each category. But Mollom has been very good, so the advertising spam attempts that get through seem relatively harmless (except for that whole part of wasting everyone's time, network bandwidth, and electricity), while other comment spam seems incredibly rude (see that "obscene, violent, or profane content" option).

No matter what the spam looks like, if it gets through, it's nice to be able to report this back to Mollom.

Mollom CAPTCHA service - pricing

So far Mollom has been free to use, and I hope it stays that way for a while. :)

To add a little more detail, the current Mollom policy is to allow up to 100 legitimate comments or up to 100 correct CAPTCHA attempts per day, with no guarantees of performance.

If you're willing to pay immediately, or you need to pay because you exceed these limits, there are two other payment plans currently offered, with the lower payment plan costing "30 EUR/month/site", and raising those two limits to 1,000 per day, with a performance guarantee.

For the most recent pricing information, here's a link to the Mollom pricing page.

Mollom CAPTCHA service - summary

Wow, it's rare for me to say this about any piece of software, but I don't have any complaints about the Mollom CAPTCHA service. 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.