How I solved the comment spam for my Django site

After this website migrated from Plone to Django, the comment spammers found my site more interesting. Instead of five spam comments a year, I suddenly got the same amount per week. Although those comments were never published (more on that later), it did annoy me. By no longer displaying the comment form below the blog entries, the problem of the spam seems to be solved. While this wasn’t my goal, it is a nice side effect.

It appears that the initial comment system (I’m using Django’s comment framework) was more interesting for comment spammers than the implementation of comments on my old Plone site was. I think this is because there is a URL field on the form now. And if the URL is present, the name of the commenter becomes a link to that URL.

Since I saw that coming, I am using a similar setup as in Practical Django Projects: for blog entries older than 60 days I’m assuming comments are most likely spam and they need to be moderated before they become visible. For the other comments, I run them past Akismet. This seems to work fine for now. (However, since I want to prevent false positives to go unnoticed for too long, an email is sent for every comment posted on the site. That is why comment spam is still a little annoying.)

Initially my comment form was displayed at the bottom of every blog entry. I didn’t like this, so I decided to only display a “post comment” link. If you’ve got JavaScript enabled, the form is inserted in the page dynamically after clicking on the link. Without JavaScript the link acts as an ordinary link and the page is reloaded with the form appended to the end. (I’m using an ordinary GET parameter so in my view function I can detect whether the comment form should be shown or not.)

Apparently this has the nice side effect that the comment spammers cannot find the comment form anymore. That is, I haven’t received any spam since this change. I’m curious how long this will last, but for now I’m happy.

Disclaimer: I don’t want to claim this is a guaranteed way of preventing comment spam. I’m just reporting my observations here…