IMO it is a legitimately useful site, but strictly for beginners, and probably only for html/css. It teaches you the basics and has the sandbox to test things out. It's fine, just not what you want to see when you're looking for actual documentation.
I used it to learn CSS way back in the day and it still seems to be a good balance between too little and too much for the beginner, so I still send my newbies there.
Not surprised it shows higher than the actual spec. I think the HN community is just getting to the greybeard stage (I'm still cutting out grays), and this is our version of JUST READ THE MAN FILE
