Wondering why users do what they do? Because you designed your site that way

"If they are going to spend that much time logging in just to leave a comment they are probably going to make sure the comment is worth the trouble."<p>I might have something valuable to say but I don't bother jumping through hoops, ever. I visit dozens of sites a day from hacker news and I'm not signing up for a dozen blogs a day. The cost is just way too high. Instead, I'll just comment here.<p>Admittedly, requiring people to sign up will stop people from posting truly contentless replies. But there some very intelligent well spoken people who just won't bother -- they have better things to do.

This viewpoint is a little developer-centric. Good design should enable users to do what they want to do as well as what you want them to do.<p>Certainly, what users want to do is influenced heavily by what you want them to do. Good design sets those expectations well.