A few months ago, I was forced to disable the comments feature as well as the forum. The amount of spam entering through the comment feature required excessive manual intervention and hackers were able to use the forum to attack the site. After taking additional precautions, I am now reopening the comments feature for all articles for two weeks after initial publication. Comments on The Rational Walk have now reopened.
The Rational Walk has set up a Facebook page for comments on articles. Please read this post for more details.