"These maps can be used in multiplayer since BNW's release. It is much easier to use custom maps in multiplayer now. All you have to do is go find the folder for the map after you have subscribed to it here. Copy paste the map's folder from my docs/games/civ 5/mods into the maps folder you will see next to the mods folder there. All the human players in your game must do this. Sounds a little inconvenient but it is way easier than what we had to do before BNW. "