Hey Don,
You have three tabs towards the left side of AC's main screen....Defaults, Favorites and My Circles. You can program each to screen in or out what circles you'd like to see on AC...so you can keep flying high, babeeee

There is no business model, per se, here. JohnR lives in Australia and owns the site and, fortunately for all of us, he's agnostic to the notion of making money from it. He derives a
small amount of revenue from hosting audio business owners that have their circles
here on AC and occasionally (tho it's been years now since the last) asks for voluntary donations at the year end holiday time to shore up any shortfall.
The thing that would cost us the most to keep AC running would be keeping a techie like JohnR properly paid to run the site.....which he graciously donates for nearly free (seriously, if he makes enough to pay for a AUS$1000 preamp yearly I'd be surprised). We all should be ecstatic we're getting a top-notch techie for the equivalent of $1 an hour to keep AC humming. AC is the Craigslist of the hi-end audio world.
John, if you've never run into him, is not the chummy sort

But, honesty is his forte...and I'll take that tradeoff over chummy any day

So, list those items on AC, it's gratis - just make them complete with pics and a real write-up, bump them forward as needed, keep the banter light and whitty, price them right and you'll see a few likely sell

John