The difference in number of comments here (17 at the time of writing this) and on the article itself (0) shows a nice example of (lack of) usability. I'm guess

The difference in number of comments here (17 at the time of writing this) and on the article itself (0) shows a nice example of (lack of) usability. I'm guessing a number of people thought about commenting on the post, then found out they had to log in, and just gave up there (at least that was my reaction). The author missed out on some interesting feedback he might've got otherwise. [apologies for being slightly offtopic for the discussion topic, but it's related to the article]