PG: The biggest source of stress for me at YC was running HN

Every forum risk having an Eternal September.

Eternal September is a period beginning in September 1993, the month that America Online (AOL) began offering Usenet access to its many users.

Before then, Usenet was largely restricted to colleges, universities, and other research institutions. Every September, many incoming students would acquire access to Usenet for the first time, taking time to become accustomed to Usenet's standards of conduct and "netiquette". After a month or so, these new users would either learn to comply with the networks' social norms or tire of using the service.

The influx of new users from AOL did not end and Usenet's existing culture did not have the capacity to integrate the sheer number of new users.

https://en.wikipedia.org/wiki/Eternal_September

Can't we leverage this lesson then? If smaller groups can be integrated into the larger one with enough time, then the answer is straightforward. You can have very large internet forums, but new users need to be slowly integrated into the 'culture' piecemeal.

Create a good culture, then break it out and parallelize it. New users get slotted into larger groups to learn the culture, then they can be sent on their way into the larger culture.

Twitter Training Wheels?

Exclusivity has been one of the primary driving factors in most major social web companies... and then at some point they just open the floodgates. I think, barring the extreme freedom of speech side like the chans, a good analysis and use of exclusivity would be a great way to do things. What gives you the "ticket in" is another topic that would take a lot of thinking and would depend on the site and it's goals.