> We've found threading to work really well with teams as small as 3. (2, probably not.) I
For what it's worth, my company is (unfortunately) very chat-heavy, and I use threads in two person conversations fairly often. Sometimes conversations branch off of other conversations.
Sure, I'm not just talking about participants in a conversation either (with the possibility of a wider audience). Even in DMs, I use threads plenty. Sometimes someone asks multiple questions not realizing that they'll branch off significantly, and threads are a tidy way to address that. I don't see why habits relevant to a DM wouldn't generalize to teams of that size too (in which case you're always DMing).
For what it's worth, my company is (unfortunately) very chat-heavy, and I use threads in two person conversations fairly often. Sometimes conversations branch off of other conversations.