Lionhead boss Peter Molyneux has told VG247 that all Fable II single-player saves are to be horded on one server for the purpose of filtering them back down in the game's intriguing co-op "orb" system, that allows you to let players into your game through floating balls of light in your version of Albion.
"All the single-player games are accumulated up to this one server and then filtered back down to you," said the developer.
You can filter the orbs you see in your game in many different ways, meaning you can only see people from your Friends List should you wish.
"There are a number of filters that filter down what orbs are seen in your world, and you can have up to 64 simultaneous orbs in your world at any one time.
"And they can be filtered down by region, so you can see the people that live locally and close to you, they can be your friends from your Friends List, they can be people with a similar game ranking as you, or I think there's one - this is purely from memory, so I may be wrong here - for people in a similar state or progress in Fable II."
Additional orbs filters may be added further along the line, too.
"If we could patch the code we could add any filter we liked," said Molyneux.
"So we could, if we wanted to - not that you can - say everyone that likes the colour yellow, or everyone who dresses the same as your hero, or everyone who's a woman: we could filter it down in a whole host of different ways."
So, in answer to your question, Psychotext, if no one on your Friends List has Fable II, you just pick another filter and play co-op with someone that has.
The question in full was: "We know about the co-op orbs for people on your Friends List, but how does co-op work if you don't have friends with the game?"
Few more to go yet.