I mean from a technical server / client perspective.

I agree that from a user perspective it can create very different "illusions" and (over the long run) even modify people's behavior - which is scary if you think about it: simple choices at the technical level can change society

If you added "Categories" to HN (group by business, startups, programming, yada yaa)

added notifications on reply

removed three-like structure

and allowed threads to be bumped

then you'd have forum which would mean that you'd have longer and deeper discussions