There's a huge opportunity for invite-only social networks because current networks are flooded with noise or contain people who don't want to talk to each other. Any network that isn't great (e.g. Goodreads, Yelp) can be rebuilt easily now. The 10x better product is the curation of people and information. The internet can't just be split between broadcast networks for everyone and group chats for dozens of people. There has to be something in between.