I don't think Imzy's scalabilities issue is what did them in. I signed up to see what it was about, and saw a JS bug and reported it, and they not only fixed it super-quick, but also sent me a thank-you sticker. So their team, while imperfect as all teams are, was at least responsive and dedicated.

If I had to guess - and I do - their problems stemmed from their community size not growing as rapidly as it could have, and monetization.

That's the interesting thing - how do you build a community? How do you build a bunch of communities? How do you advertise, how do you tackle moderation successfully, how do you keep people invested, etc.

There's a billion write-ups on writing code, but nowhere near enough on running a meta-community.