> But to your point, I think the network effects are much, much, much stronger than anyone (including Theil, from which I first heard this concept) had ever anticipated.> So maybe the question is how does one beat the network effects that are so prevalent?
You can't. And in fact, these doomed-to-be-shut-down sites are in fact exhibiting an extremely strong network effect. The founding group of malcontents has an existing network of relationships with both strong and weak ties, and the whole lot of them get pulled in en-mass.
That's what you have to overcome in these cases, not the network effect that the mainstream sites exhibit. FB, Reddit, and Twitter don't necessarily have to be beaten in order for a smaller site to succeed on it's own terms.
There are tactics that would make it likelier for such a site to endure, but the site would have to commit at the outset to a whole hearted strategy of weapons-grade muffling of the toxic sludge. Pretty much implement every undeployed UI trick and algorithmic tweak that can be found in the recent FB leaks. Implement shadowbans. Use rate limiting. Suppress the display of posts that have a higher ratio of angry emoji reactions. Brigade detection. Virality and repost limits.
Anyway, if you're willing and prepared to dial the soft-moderation and filter-bubbles up to 11, you MIGHT be able to run a free-speech-centric site that is capable of withstanding an influx of Nazis and Trolls without degenerating into a festering cesspool that repels anyone else. But you're going to have to have a crew with pretty strong stomachs looking at all the sludge just in order to continually maintain and adjust the knobs on those measures.
None of that will be cheap or easy, and in the end you'll have accomplished a rather dubious feat: a site that allows conspiracy theories and racist Nazi rants to be posted while limiting their spread as much as possible. So you can 'friend' your crazy uncle frank and comment on his fishing photos without having to deal with his anti-masking posts or Alex Jones fan-fiction.
Of course the folks you're muffling will complain loudly, but realistically speaking that won't prevent them from using the site.
I'm not sure you can build a viable business model around that value proposition, but from a technical and social standpoint it might work.