To answer a few things, yeah, the focus here is on preservation. This is a really massive undertaking, and it's gonna look kinda sad and silly until we get further in. The site's only been up for literally a month, so as far as content goes, we have a decent amount of it.
I don't see the issue with "all these sites have tutorials of varying accuracy, timeliness, and completeness, so let's create a central, fact-checked resource for it all". For now, linking to other sites is good enough, but I think we can do better, to make sure it's still around in the future. I can't guarantee TWHL's continued existence, or Interlopers, or the SC forums. I can guarantee our own site.
And so far, we're really only touching the stuff documented elsewhere; there's plenty of cracks in the documentation, like the aforementioned NPC persistence issue. It's stuff we take for granted, but would confuse anyone just starting out. I want our knowledge of GoldSrc and Source to be airtight one day.
GoldSrc, by nature of its documentation being so spotty, is a key focus of mine. This site came out of my own personal need for it, and I figure someone else could get something out of it too. If not now, then at least in the future.
I personally have been writing daily for the site, but my knowledge only goes so far. If you're interested in helping, I'm far more active on our Discord server, which I'll leave here. I'll be working on coordinating some way for other people to contribute. Right now, it's literally just "send me a text file and I'll edit it and put it up". Maybe I can get our webmaster to code in user roles or something (weird custom NodeJS install), or at least a submit content page.