I was on this site a lot about 5-7 years ago, I believe. I was given a set of decent B&W monitors, and I started paying attention to my stereo system. Before that, as with a lot of musicians, I only paid attention to music production gear and sound with regard to gigging or recording. Then I spent a couple of years really listening a lot, which coincided with a hiatus from playing much. During that time I bought a boutique pair of speakers through AC, and spent TONS of time geeking out, reading argument threads, and other fun stuff.
After a few years I moved on, because I was essentially happy with my modest but good sounding gear, and re-focused on musicianship and related things. I didn't post or check audiocircle at all for some years. Now I'm back fiddling and trying to get a nice sound in a new house, so I checked back in a month or two ago. I can say that the site seems way slower than it did before. Fewer hot threads, topics tend to get few and dispassionate responses, etc. The thread that's hot now is basically people ordering amps. Which is kinda uninteresting, at least for an 80 page thread. IMO.
Just my sense of things, but maybe it's cyclical and comes and goes, and I just happened to be around for an 'up' period before.