Well, the the article pointed out one way... Have a community somewhat gated by the need for technical proficiency, and have a bigger, shinier, "popcorn internet" alternative (facebook) to bait the normies away from it. For example, suckless programs are configured by compiling them from source. This is for several reasons, but one explicit one is that it keeps away less technical users, keeping the userbase "small and elite".

The eternal september happened when the manswarm flooded in; you can't bail out the flood, but it'll drain to a lower-common-denominator cesspool if one is available, and you might be able to build a high enough tower to stay above the waterline.