I merged my stream server and our vanilla server into one server. The vanilla server has been updated to 1.11.2, and it hosts the main stream server world, our original (1.10.2) island world, and an older Minecraft world I hosted on a local server at school last year. The different worlds are all accessible from a portal room with return portals to and from their respective locations.
There are plugins on the server that handle permissions, and the default group for new users has no permissions to do anything (essentially just to spectate). Multiverse handles the portals, Essentials and WorldEdit/Guard handle anti-grief, and, of course, there's a TreeCapitator type mod to make life a bit easier. There is no whitelist, since I let permissions handle new and unknown people (useful in case a stream viewer wants to connect.)
Anyways, it's a relatively active place. I've seen 7 players connected at once, and there have been shenanigans more than a few times. Normally there are two or three people online just doing whatever, though.

We are each a beautiful and unique snowflake that will melt in hell.
I got the words "jacuzzi" and "yakuza" confused.
Now I'm in hot water with the Japanese mafia.