Associate producer Sylvain Trottier talked GRTV about the Jackdaw and social features in Assassin's Creed IV: Black Flag.
"Discovery sharing is one of the online system that we implemented in the game. So the idea is to try to break a bit of the loneliness. So you're still going to play in singleplayer, you're still going to be alone doing your own missions. But your friends can still add markers on your map. So if I find discovery sharing treasures. These treasures are put in the world by our servers, and once they are put there, once you can find them the location of this treasure is shared with all your friends and they're timed based so the treasure is going to be there for a certain time and then disappear."