If you mistakenly click the wrong one of the two very miniscule arrows for a vote, there is no way to fix this mistake;
New users can make unpopular comments which will auto-ban all of their future comments -- even when they say things worth discussing -- and there is no way for them to crawl out of that hole (and worse, they often don't even realize that it's happening);
Reply pages tend to expire while writing long, well-researched, carefully-considered comments, requiring those rare commenters to copy-paste the contents of their reply (and worse, inadvertently discouraging deep discussions);
Users are never notified of replies to their comments or submissions, which in effect motivates people to spend more time on the site polling it (as opposed to a useful push-type notification), and also effectively limits discussions to a du jour shallowness because an active user is unlikely to notice any reply made to them a few days later.
I'm not so certain that the author of that article would find this little forum to be a suitable example of his kind of "complex simplicity". I think it's actually a bit the opposite: the internals are simple, which requires more complex behavior on the part of the users.
That point number that everyone seems to want to attach to everything these days has absolutely nothing to do with measuring worth.
It is merely a measure of popularity, and popularity doesn't even correlate well to value.
As an analogy, gold would be a worthless piece of metal, if it wasn't for its popularity. Worth is an illusory, human-defined concept and just like anything "the worthiness of something" is ecided by majority. Perhaps because those who don't subscribe to majority's value system are weeded out in the process of evolution, unless their value system offers some incredible evolutionary advantage. And by incredible I mean "everyone is dead and unable to reproduce except for those who think that karma points are bullshit".
In reality, reality is merely a construct of our minds, and all value systems are created by consensus on which hallucinations are advantageous and which are disadvantageous. Thus, if we decide by unspoken consensus that karma points are worthy of construction of smart comments then karma points are valuable.
I would love to sit here and debate this with you, but I have a Saturday lunch meeting in a few minutes with my old high school's football captain and prom queen. I hear that they've accomplished some amazingly valuable things. We're probably going to eat at McDonald's. We will probably spend some time discussing the latest Dean Koontz or Danielle Steele novels. After that, I will come home and watch Fox News for a few hours, followed by some sitcoms.
Gosh, it's a good thing all these are so popular! Otherwise, I would have no idea what was valuable and what wasn't.
Oh, and by the way: gold would not be worthless. It has certain intrinsic properties -- like its resistance to corrosion, its malleability, its conductivity, and its low melting point -- which have made it valuable for many uses.
As an extreme example, consider value system of a heroin addict, for instance. He or she values heroin above all. You might say his value system is inferior to yours, but how would you defend that statement? Speaking from utilitarian point of view, it's not necessarily that a heroin addict decreases society's happiness or pleasure, if he uses it as a constructive stimuli.
Speaking from a physiological point of view, we are not much different from heroin addicts. My opinion is that value systems are psychological routes by which we can get an endogenous high. Our brains have built a series of quests for us to accomplish, after which they reward us with various pleasurable chemicals.
Some people get high watching Fox News, some people get high debating philosophy, some people get high from heroin. The value of each activity is (non-verbally) agreed upon, by spending time on that activity and hanging around people who spend their time on the activity.