At $WORKPLACE I've been observing with interest the different species of interactions that can happen during group chat. Let's divide them into three different areas.

$WORKPLACE_ALPHA -- An agency. This was fun, we set up bots that created a lot of noise in the channel. Remember this was pre-covid, so the chat service in question, HipChat, was a side channel, not a hard requirement for communication. Everything was conducted in a single main channel, all real-time work collaboration went through here. There was no threading. As the team was small, we were all able to keep track of things fairly well, we would sometimes go into DMs if things got complicated.

$WORKPLACE_BETA -- This was a much more stoical workplace Slack, with zero real "banter" and no arguments. I felt quite apprehensive about posting in this Slack. There were only a few channels and little activity; few problems required real-time collaboration to resolve, and if that did become necessary, it was done in DMs. Email was still heavily used here.

$WORKPLACE_GAMMA -- They use Slack as a real "replacement for email", in the way it's supposed to be used. This means a lot of channels, a LOT of threading, heavy reliance on emoji reactions, and while it does feel casual, there's also not much off-topic chat because of the emphasis on signal.

There is still heavy disagreement on the relative merits of coarse-grained vs fine-grained channels. I tend to favour coarse-grained channels, but on the other hand, when you have automations and other non-natural inputs affecting channels, channels can end up functioning more like a specialized Twitter stream or similar, in which case that channel does need to be fine-grained. It's clear that there's a positive correlation between large and coarse-grained channels and off-topic banter. (I don't mean to thereby claim that fine-grained is preferable, or the converse.)