4 pane comic of dolan on the left and spooderman on the right
pane 1 (dolan): cum join opensurce cummunity!
pane 2 (spooderman): shure! how joyn?
pane 3 (dolan): Here discord! (with discord logo)
pane 4 (spooderman with tears in eyes): y u do dis?
Discord does have threads. I think the server admin has to enable them though. In rooms where it's enabled, you can choose to post a thread or a regular message, and people can create a thread by replying to a regular message and choosing the option to make it a thread.