Start from a small island, build a small town first and develop it to a big city. Build pirate ships, starting from small shallops and ending huge Ships of the line, Galleons and fast Frigates, manage multiple fleets performing tasks such as killing monsters and plundering other cities. Hunt other pirates by intercepting their fleets on their way. Steal their gold, weapons and other resources.
This is an MMO game, which means you can play with your friends, or find new ones in the game. Form alliances, chat with your teammates, organize raids to kill huge monsters together, join with your friends to perform more powerful attacks.
This is a RPG as well: you can play an evil pirate, who attacks everyone, steals from everyone or you can be a honest pirate, who helps their friends, revenge their enemies or, you can even choose to never participate in battles and be a peaceful pirate, who grows carrots, it's up to you!