Also,
right now there are 3 game modes, that I can tell. Open world, private, and solo. All three are the exact same game, same systems, etc. You log out at a station in one, and you'll be in that same spot in another mode. The difference is that Open = PvP. Private = private group of friends, etc. Solo= just NPCs.
edit... and I realize that's not what you were asking... It's all essentially one server, but some star systems are more governed than others... I went on a killing spree in one and racked up 130K credits with no fines. In another system I attacked a "wanted" ship that was fighting federation navy npcs and still got hit with a fine.