[nonethewiser]

I didn't know about Zulip stream/topics but heres my naive tl;dr after reading about it: Streams are like slack channels, topics belong to streams and have no analog in slack. They are essentially sub channels. Or tags/categories within the stream scope for your messages. Although threads (if people use them) arguably serve a similar purpose on slack.

I wonder, is it possible to message on the base stream, or only topics? I feel like if you cant comment on the base stream you always need a general topic. Otherwise you're going to keep making new super-niche topics or make topics "off-topic." And what happens when discussion on one topic ventures towards some other topic? To bridge the gap it seems like I need to make a new message in the other topic and link in the original one.

Generally speaking, I do not like forcing these structures on the "write" side. I had the same problem with Arc browser (with respect to types of tabs, workspaces). I don't want to have to essentially define some metadata about the action I want to perform. I have the same attitude towards taking notes. Generally speaking I'd rather have powerful tools to discover, re-organize as I see fit. I guess maybe this is less true in a messaging app though because you already have to choose a channel either way.

[terpimost]

If you write message without defining a topic it will be in (no topic) topic. You can move messages from topic to topic https://chat.zulip.org/help/move-content-to-another-topic