Many streamers and youtubers create discord servers for their fans. With discord servers, you can create as many channels as you'd like for different things. One could be just for chatting, another one for chat debates, or another for video games. You can control who can speak in which channel, so sometimes for a channel that might be for announcements, you'd only want the owner or admins to talk there. You can also add voice channels where people can use their microphones to talk with their voices. You can join with your voice at any time, whether there's only 2 other people there or 20 other people in it.
I created my own server for my viewers that can join from my stream by using a command in my chat. The command gives a link to the server, which sends an invite to join the server to their discord account. Anyone can join, unless they're banned by me or an admin or moderator. I have about 7 roles, and the main ones are the "mod" role, "VIP" role, and "subscriber" role. I have a channel for chatting, a voice chat for talking, another voice chat for minecraft chat, a rules channel where no one can talk in, but I have a lists of rules for the server in, and even a channel for alerting the members when I live stream.