If you have a stable community, there is a certain distribution of participants from recently-joined to oldtimers. The bulk will have experience with the commu

If you have a stable community, there is a certain distribution of participants from recently-joined to oldtimers. The bulk will have experience with the community's unwritten rules due to experience; new folks constitute a tiny minority and and "infraction" of theirs can be gently corrected. This no longer works when suddenly scaling up participants. Behaviour by inexperienced members goes uncorrected and drowns out the original behavior. Aspects that were frowned upon can become the new standard. In short, the atmosphere changes - and no one genuinely controls the change's direction.