[fladd]

Oh, sorry, I didn't know Discord gives people their own exclusive servers to host their rooms on for free. I assumed you just create new rooms on their main server, in which case it would be comparable to signing up to the matrix.org homeserver for free and create as many rooms there and invite as many users to those rooms as you want.

[Johnnynator]

A "Discord Server" is just a Room where you can create your own text and voice channels. Nothing comparable to hosting your own Matrix instance.