To clarify my thoughts when I brought it up, it seems like the canonical example of this problem is a dating site: sockpuppeting seems somewhat unethical, and somewhat impractical (can you flirt with the guys who message you, but manage to tactfully reject suggestions of meeting? Do you have multiple sockpuppets per state? etc.), but without a seed the site is worthless.

I guess it would help that when someone signs up, they don't need to come back for people to send them messages. So maybe you don't need a community like reddit did, just users. But I don't know.

Does anyone know how sites like OKCupid solved this?