Yes it is particularly social because it has the concept of Karma. It has tamed it by policy but vanity can never be tamed outright. It will always exist in some form on these networks and HN/Reddit style forums capitalize on humans’ vanity by appealing to it through Karma.

Thus it ticks up the social-ness score a bit for sites like HN as opposed to some old forums like one would find on Yahoo or used to find on Compuserv.

Karma and the wisdom of crowds gives way to herd mentality and vanity. It is what drives the form of discussion on these sites.