I think that the way HN is set up encourages people to contribute interesting and engaging content (not to mention comments). As for (a), I see what you mean.

I think that the way HN is set up encourages people to contribute interesting and engaging content (not to mention comments). As for (a), I see what you mean. I think, seeing as I only recently started really getting into new aggregation, I haven't found my niche yet. I appreciate most topics on HN and they usually have some form of impact on me (developing my first Python application at the moment). Maybe once my likes/dislikes are more defined I'll want something that isn't regularly found on HN (at point I might just start posting it to HN -- there's got to be someone else out there with the same opinions as me).