In Windward, you're able to help towns, do missions, gather resources and fight pirates. Fulfil a town's resource request and it can grow, offering you more quests and items—eventually letting you upgrade to bigger and better ships. Essentially, it's a big naval sandbox game (in the water). It also supports co-op, letting you travel with a flotilla of friends.
The game mixes RPG, MMO and RTS elements.