> Seeing the same people in the member list every day, exchanging little inside jokes
...about what other people are writing in the main communication channel, creating precedents about what should be discussed with "individual members of the community on a personal basis" and deciding the content that should be written on the main channel for the benefit of outsiders asleep in other time zones, ...
How can you generally prevent a subgroup "deciding the content that should be written on the main channel for the benefit of outsiders asleep in other time zones" even in an 'asynchronous' communication channel? There's nothing stopping them from responding to each other quickly enough to effectively communicate 'synchronously'.
I've intended to reply to communications before only to discover that someone else replied first while I was asleep in my other time zone.
...about what other people are writing in the main communication channel, creating precedents about what should be discussed with "individual members of the community on a personal basis" and deciding the content that should be written on the main channel for the benefit of outsiders asleep in other time zones, ...