I think that a lot of the problem is also due to the desire for instant replies. Patience seems to be increasingly lacking, particularly online, as people are not willing to wait. They want instant one line responses and dialogue, and this is one reason why blogs, Facebook, and Twitter attract more of the younger generation who used to come through to post on forums. Note my use of the plural there, it's important. I am on the team which produces the very forum software which 40K Online (and other forums use), and forum use and activity across the internet has fallen sharply during the last couple of years. This is not, therefore, a 40K Online specific problem.
I think that it's also worth saying something about the state of the game, age, and real life. I've seen more people stop participating here because they don't play the game any more, or have too many real life commitments to play it any more. This is what often happens the older you become, and 40K Online's main contributors for many years have been the same people, but as they have dropped out, mainly for the reasons that I've indicated, so activity has fallen because the younger generation who would have come through to replace them prefer to use Facebook and Twitter. When I think back to when I started here in 2008 on the Eldar boards, and the people I used to work with reviewing army lists and producing articles it always gives me quite a shock, because I'm the last person still standing from that group, and I don't play the game any more either. It's a sobering thought, but there's nothing to be done about it. It's not possible to force people to keep playing 40K.
In essence, therefore, it doesn't matter what the rules are. If people aren't playing, don't have content to draw them in if they are playing, are too busy with real life, so prefer to post one liner Facebook style comments, or have moved on to other hobbies, then they're not going to come here or to any other forum.
I find myself in complete agreement with the article about comments. Unmoderated comments are just awful. You need only look to You Tube for examples of this. The way in which people attack each other or troll on there is just horrible, and on forums which are poorly moderated, you end up with a similar situation too. There is a reason why I ended up doing most of my 40K related posting here. The content was a massive factor, of course, but it was also because the sort of lazy, sloppy, and down right rude posting accepted elsewhere wasn't acceptable here. If, and that's a big if, the majority wants the sort of comments which You Tube provides, then I think that this says more about the mindset of people than it does about moderated forums.
Finally, if comments were the answer to anything, then you would think that when the option to use comments on forum members' profiles was enabled a couple of years back, there would have been an upsurge in activity. They have barely been used. A comments system, as the author of the article suggests, is not the key as to whether a site attracts people. Content is the major driving force.