Oldhead here as well. Yeah, the magic of discovering this place back then was incredible, and the discourse so intelligent. There was more of a kinship I felt with the old squad; I really cared what everybody thought and was much more engaged. I miss the old group, a very small village. There are newer posters who are just as intelligent, but the S/N ratio has definitely declined. Or maybe I've just changed.
This happens on many sites, and in many cases I'd attribute it less to a reduction in "quality," and more to a decrease in homogeneity: a successful site attracts more people, with increasingly disparate backgrounds.
For the original users, who were charmed by the fact that "everybody has (more or less) the right opinion, and we can discuss rather than argue!" this can be a shock, but I'd venture that it's often actually a rather healthy thing, even if you unfortunately also get more trolls and flamers along the way. Pleasant as it is to talk with one's close peers, one can often learn more by talking to people one disagrees with...
It can go bad, of course, but HN certainly doesn't seem to show the usual symptoms of an internet cesspool; based on my short time on HN (~1 year), the S/N ratio isn't bad at all.
I was thinking we could prove this with a blinded quiz: show you a post with no date or author, ask you to rate the quality, aggregate the results.
But it'd probably be too difficult to truly blind it; posts would reference startups or frameworks that didn't exist five years ago, or Obama, or other anachronistic events.
