For many years, I have never seen this site appear in search results (Google). StackOverflow is often top two or three results. Possibly it's an SEO issue or possibly somehow momentum
Popularity? Nearly Javscript everything...
About a year or so ago here when I looked in I saw a bunch of weird posts - people attacking others. I know too well how hard it is to help people online, but this seemed quite spiteful to me.
Slack. There are so many communities of varying size where there is always somebody around to help out.
I learned so much from this place - I've always looked in over the years (didn't always post though). I noticed years ago this place was slowing down - I could never even answer questions because they were ALWAYS taken care of. I think the best thing I learned from this place, beyond just PHP, was RTFM.
Forums are totally dying. Did you notice that there was a major IRC announcement today? Maybe forums will have their day again, too.