Invite only networks were you're responsible for the people you invite à la what.cd : your invitee does something against the rules? They get banned and you get banned.
Maybe some percentage of invitees? I can definitely see the need to disincentivize imprudent inviting, but one mistake is pretty rough. Surely you’ve met somebody in real life who’s revealed themselves as a jerk after initially appearing ok.
Haha that's my line! I would guess that those people who are already on the seafood website know other technical people in their day-to-day workspaces like silicon valley or Palo Alto or wherever, so it's easy for them to get a link. Meanwhile for those of us on the opposite side of the US or, barely in the Anglo-Sphere at all, we are on the outside looking in and are not likely to get a link just by being mostly lurkers and occasional contributors.
At least for me, I'm the only HN user I know except my dad who doesn't even post, he just got lurk links from his knee if the woods like hackaday.