I think it’s still early days here, so getting stories from people about how they’ve gone about this and what kinds of things have come up along the way will be interesting.
In general, we’ve often suggested that sites which have been around for a while trying things out first among their site staff or a small circle of high-trust members. This may not be the end goal, but it’s a safe way to introduce the feature into an existing community and try things out. The chat_allowed_groups site setting can be used to control which groups have access to the feature.
I’d consider what patterns you see in terms of how members currently interact and overlap in time.
Are there existing topics with a lot of high frequency back and forth? Are there groups of users who need to interact more closely in some way? Maybe channels for those groups or those kinds of discussions would be worth trying out.
If, on the other hand, most communication is very asynchronous currently, then I might look at it the other way – is there some kind of more synchronous communication that would benefit the community that is not currently happening… What would that look like?
You may hit a number of false starts as you try channels out for things where the participants are better off discussing things asynchronously and do so well. When the people you want to include in a given discussion aren’t all around at the same time, and it really is better done in a topic. Finding those cases where it really helps those groups who are around at the same time get things going more quickly in chat or have a little more fun doing it along the way may take some time.
We’re still exploring this ourselves on meta, and I think we’ll end up with a handful of public channels for different thing at some point, but aside from some dedicated channels for staff and a couple other groups, many of the ones we’ve tried out so far have been rolled back into #general::channel.