The Two Realms of Gameplay
Setting aside story-only posts for the moment, Gameplay falls into two realms: action posting and combat posting.
Action posting is the taking of any non-combat action by a unit under your command at some physical place in the Galactic Flashpoint galaxy. A Star Destroyer entering hyperspace from Coruscant is an action. A Calamari Star Cruiser deploying its X-Wings is an action. And so on.
Combat posting is the taking of any action in a place where any number of hostile units are currently present, on the surface or in space. A Star Destroyer firing it’s turbolasers at Corellian Corvette is a combat post. And so too is a Calamari Star Cruiser deploying X-Wings if it is doing so at a planetary system where hostile units are present.