[johnnyanmac]

>While I do think a good community needs some type of gatekeeping, being invite only is not it.

Their verification method already seems to be enough of a gatekeep.

>if you don't know (or can't find) an existing_user from whom to request an invitation, you can make a public request for one. This will display your name and memo to all other logged-in users who can then send you an invitation if they recognize you.

And they ask for some personal website to verify as well that is visible. Given the volume at this scale, this could have been a manual verification by the creator for a while until there's enough scale to rely on invites (similar to Tildes).