Allow creators to upload worlds as either Public, Friends or Private. Public and Private already exists. However the Friends one would allow users on your friends list visit them. I know lots of people only upload worlds so that their friends can hangout in. These worlds would spawn a private invite only instance.

These worlds could be either approved or non approved (like private worlds).

If this is a double post let me know so I can upvote the idea.

More thoughts are welcome too.