It suggests that instead of displaying "0 comments", you invite the user to be the first to comment. It's one more of those little tips that in the aggregate raise a blog or website above the pack. The article is well written and worth a look.
Thanks a lot Russell. I've been blogging for over a year, so I've had time to come up with little tricks and experiment with different techniques such as this which in the long run can have a big effect on how your blog or website performs.