Its seems to me that this si growing very big! like the Flight Simulator Unlocking Your wings of Steel Bronze etc.... But in SSE you will unlock many items from the Following
"The sailing will be woven through three different story campaigns and 24-player free-roam maps. (Co-op missions will be added after the game's release, according to VSTEP chief marketing officer Frank Dolmans.) We got details on two of these three single-player campaigns. In one, you sail a cruise liner to ports such as Marseilles and Bora Bora. Not only do you need to keep your passengers happy, but you must cope with finding replacement parts and putting out fires. The Greenpeace campaign sounds more intriguing, however. Here, you will sail the Antarctic seeking to put a stop to the illegal whaling occurring there. These missions are based on actual circumstances, and the game's unlockable rewards include interviews with the captains who experienced these scenarios. Less-interesting unlockables include postcards and newspaper clippings that proclaim your triumphs."
This is from the E3 Expo Interview i got from ShipSims Twitter Page
