1. Make the website invite-only. 2. Give out X invites to everyone. 3. Every user now has a reference pointing to who invited them. 4. Require that you must

1. Make the website invite-only. 2. Give out X invites to everyone. 3. Every user now has a reference pointing to who invited them. 4. Require that you must vouch for the behavior of the people you invite, and their behavior may impact your participation. 5. Use tree traversal and analysis for pruning bad sections of the population of users. (i.e. If you see a series of bad users, go up the tree to find the source and prune it there.) 6. Work on algorithms and moderator tools to improve said analysis. 7. Give merit and incentive to those who contribute. (See: Slashdot and Everything2 systems.) 8. Add anonymous meta-moderation. (Again, see Slashdot.) 9. Give ranks and small power to users based on their merit and participation, and somewhat based on their invited friends. I can keep going. It's a bit harsh, but I feel it'd work. I've considered making an example app, but the hard part would be getting a critical mass of users and content. Reddit, for example, faked posting content for their first few years to seed their community. It's hard to grow a new community, if even possible. P.S. If anyone has a lobste.rs's invite, lemme know. Curious to see how their invite-only website has progressed.