[rockooooo]

Zulip is more of a Slack-like instant chat system with threading as a first class citizen; CQ2 looks like threads only exist in the context of one "root" document vs a channel in zulip where threads can intermingle.

[anandbaburajan]

And neither Slack nor Zulip are suitable for complex discussions.

[alya]

Zulip's core design goal is to make it effective for complex discussions, and our users tell us that it's working. E.g., cutting-edge math research https://zulip.com/case-studies/lean/; Rust language development https://zulip.com/case-studies/rust/.