Originally posted by Frozztastic:

Servers are almost always password protected. So unless you have a friend that you are playing with, or find a group in a LFG channel, you'll find that across the board.

The problem comes with the fact that..well...who can you trust to not destroy/take your stuff? Glitch out your world and make it unloadable?

Too many problems for open multiplayer.

As for not being able to join friends, try using the Google for ways to connect to them, as I'm dumb in that area.