I think you vastly overstate the size a network effect has to be before you hit critical mass. Especially for interest-related things. For instance, the Haskel

I think you vastly overstate the size a network effect has to be before you hit critical mass. Especially for interest-related things. For instance, the Haskell subreddit has 73k members. But members on Reddit isn't a good metric (I don't even think I'm one). There's typically a hundred or so users at a time. It's not huge but it works. I'm on chat servers and forums with less than 100 active users and it's plenty to spend years participating and following along.