Typically I share what I find interesting and I click on the comment hubwheel if I think the comment is thoughtful, no matter if I agree or not. The hubwheel, like Karma or any other point-based system, becomes like a game with rewards. I think people like being rewarded, even for something as trivial as being able to award another user a badge. Hopefully, the system here encourages engagement and thoughtful commentary. Its difficult to tell, because its a small community, which I think by nature is going to be more respectful and thoughtful, since everyone kind of develops a "personality" of sorts, which the rest of us come to know in some way. If this site were orders of magnitude bigger, then we would see if its the format or the people make it great. I suspect the format is an improvement over what's out there, but its still the people that count the most by far.