I have recently begun to realize that there are 2 aspects to "website degeneration". One is the obvious new people showing up because they heard it's cool psuedo python paradox situation.

The other comes from the old-timers themselves. I'm not particularly that old-timer, but in the 3something years I've been here, I can say I have experienced this:

I've grown.

The "5 awesome vim tips" or "super deep closure stuff" articles that today annoy me as fluff were deep and new to me back then. HN was a fantastic site introducing me to amazing things, and it is introducing a lot of people to the same amazing things now. As such, the quest for truly new content needs to go deeper, but the people who need the lighter content are greater in number and enthusiasm, ensuring the fluff rises.

When the older crowd doesn't notice their growth, or the lack of change in content (or the combo) you start to get "it's gone down-hill" type comments.

edit: I mean the quest for truly new content for me needs to go deeper, not that the site necessarily needs to go that way.