What's the difference between a public and a private slot?

When I set up an internet-connected game of Dead Island, I'm allowed to specify how many public and private slots I want to have available. What distinguishes them? Ideally, I want only my Steam Friends to be able to connect to my games; will setting all my slots to private do this?


Solution 1:

Public slot means that anyone can join your game via matchmaking.
Private slot means that only your friends or invited people can join your game.