It's so simple that we actually focus more on the content than anything else Let's also not forget the fact that the content is aimed at a fairly narrow niche.

It's so simple that we actually focus more on the content than anything else Let's also not forget the fact that the content is aimed at a fairly narrow niche. If HN were aiming for mainstream popularity, I don't think it would work so well. Now, presumably this focus may also be the case in some sub-reddits-- but then you fall into the opposite problem; the permitted topics can be too narrow. Put another way: there's a complex set of mutually reinforcing relationships between the community, the content, and the system. I don't think you can reduce the cultural differences between Digg, Reddit and HN to any of the three.