Passwords, user accounts, email verification. I have never liked requiring my website's visitors to register before they can leave a comment. There is a large segment of people that like to submit quality comments online, but they don't want to be required to leave their personal information there. So from the beginning, I have always allowed anonymous commenting by unregistered visitors and for the most part, they quality of the comments haven't suffered. However, allowing for anonymous comments also invited my site into a war against comment spam. My latest weapon to do the fighting for me in this war is Mollom.
I was first introduced to Mollom in the Fall of 2007 as a beta tester. Prior to Mollom, I had been using a number of techniques, modules, and services with limited success in blocking unwanted spam. While some of these filtering methods did help me filter out unwanted content, I was still spending quite a bit of my time moderating the comments for potential spam. Worse, in long absences from the site I had to disable anonymous commenting for fear that I would come back to a site riddled with ads for the latest popular pharmaceutical drugs or some girl that wanted to be seen for a price. That's when Mollom entered the picture and helped stop most of the spam from entering my site.
In the two years since I've used Mollom, the service probably has blocked more than 100,000 pieces of spam from being posted at my site. Since, the current statistics provided by Mollom only date back to early 2008, the official number of spam blocked stands at around 77,000. In other words, I receive an average of 120 comments a day that require no moderation on my part.