Discovering is a system which allows the player to send out sailors to discover the world in order to gain Reputation, Silver in addition to other items you may find while exploring such as provisions and other items and equipment. Upon successfully finding a Discovery you will get Maneuverability, Voyage and Profession XP as well as a logbook which you can take to an Identifier and get Reputation and Silver.
Discoveries, usually referred to as "Disco's" or "Sparkles", are usually found on the High Seas and can be found using sailors to get logbooks which can give you reputation and silver at any identifiers in one of the major cities. Discoveries can be located on High Seas by sparkles that appear when you sail over, or near, a Discovery.
Most main cities have an NPC called the Adventure Alliance Master that gives quests to go and find certain Discoveries and will reward you with Silver, Experience, Reputation and sometimes Items, when completed.
Other Discoveries include Plants, Animals, Shells, Treasures and Locations. Shells and most Treasures can be authenticated right away but other things like Animals or Locations require collecting an item in order to authenticate it at the Identifiers. These items are sometimes referred to as "Auth's" by players.