I'm not clear on whether SN itself is going to allow for the creation of different boards as per subreddits, but I'm very confident that eventually there will be a family of sites running the SN software, bc the paradigm is just too good.

The only question (to me) is whether they're under the SN umbrella, as per reddit, or if it's just different people running the same code, as per Discourse. (Or Discord.)