[jfrankamp]

A more specific slack channel (and I assume mattermost channel) is a thread that you can add people to any time and they will immediately have history. Or put in the inverse, a Zulip thread that is too general is a channel with information overload and becomes useless. Does the nesting have intrinsic value over simply more top level channels?

[aidenn0]

Mattermost has threads inside channels as well, but they end up underused since posts need not be to any specific thread.

The idea is you subscribe to a channel, but then any post to the channel needs to also have some sort of logical subject.

[tabbott]

Right, in my view it's important that every message have a topic/thread. The reason is that you spend most of your time/effort in a busy team chat tool consuming other people's messages, and that flow is a lot more efficient if you don't have a giant "catch-all" bucket of unthreaded messages about fundamentally different things to wade through in order to find what's important to you.

Zulip, used well, ensures that the messages are partitioned into different conversations, so you can easily do things like skip to the bottom of a long thread to see if it ends in a satisfactory resolution, without missing the unrelated question that you need to answer.