Did you play the Outer Ops missions in Metal Gear Solid: Peace Walker? It was a little meta-game thing that let you send your soldiers to take on various conflicts around the world. It was a risk/reward system, as you could gain valuable resources while potentially losing, if not all, of your soldiers. 

This meta-game happened in-between missions, and while you could totally ignore it I found myself addicted to the idea. I've been saying for years now that someone needs to take that concept to the mobile space and tie it in with a core experience on PC and consoles.

Ubisoft has heard my prayers and Assassin's Creed IV's mobile companion app will have a similar meta-game concept going for it. In the console and PC version of the game, you'll be able to steal enemy ships and add them to your own fleet. In the fleet missions on mobile, you'll be sending these ships out to do whatever it is a pirate does out in the open seas. Any money your fleet has earned in these missions can then be applied to your main game.