[II2II]

Perhaps it is because I put a heavier emphasis on the word media, but I don't really classify HN as a social media site. It's more of a forum where people discuss submitted articles. The dynamics are entirely different.

For one thing, there is a lot less "attention seeking" behaviour. While YCombinator and associated companies use it as a promotional tool, it is muted. Some end users may use it to drive traffic to their blogs or show off their skills, but it usually comes off as humble and related to common interests (or maybe the blatant self-promoters rarely make it to the front page). Even though some of the people who frequent (or pop in) here are more recognizable, I doubt that anyone is trying to win a popularity contest.

I think stuff like that is important when considering the psychological impact of a site. For good or for ill, reality is reality. In contrast, social media sites tend to be driven by fantasy: fame and fortune for creators, endless exponential growth for investors, and all of that nonsense. That distortion of reality can be damaging for those who either seek to achieve it and for those who feel they will never measure up.