Money printing, player trading, gold selling - in game economy explanation in Ultima Online. Good read Frontier 
So there is a problem right now because we need proper crime punishment system which wont be exploitable, for example: there can't situation where someone participating in piracy is rising his bounty, then his friend is killing him, getting and clearing the bounty and the player with bounty just rebuy his ships for pennies - this is money printing. The money must be taken from bank account already existing in world. It may be add to pirate rebuy cost or victims may post bounty vouchers with their won money - the system require true money flow. It is important because money flow is driving force of emergent social gameplay. It force players to cooperation, trading, talking, working together and fighting. Money printing create artificial, closed, almost dead environment without leaving breath. It becomes static when money is printed by systems.
This quite interesting case study of Ultima Online which have player based economy (at least partially): http://www.mine-control.com/zack/uoecon/slides.html
Of course I have it strong and weak points, still it is good starting point for Elite money-flow-exploits-player-trading-gold-selling problems which should addressed and fixed in future and whole economy expanded.
So there is a problem right now because we need proper crime punishment system which wont be exploitable, for example: there can't situation where someone participating in piracy is rising his bounty, then his friend is killing him, getting and clearing the bounty and the player with bounty just rebuy his ships for pennies - this is money printing. The money must be taken from bank account already existing in world. It may be add to pirate rebuy cost or victims may post bounty vouchers with their won money - the system require true money flow. It is important because money flow is driving force of emergent social gameplay. It force players to cooperation, trading, talking, working together and fighting. Money printing create artificial, closed, almost dead environment without leaving breath. It becomes static when money is printed by systems.
This quite interesting case study of Ultima Online which have player based economy (at least partially): http://www.mine-control.com/zack/uoecon/slides.html
Of course I have it strong and weak points, still it is good starting point for Elite money-flow-exploits-player-trading-gold-selling problems which should addressed and fixed in future and whole economy expanded.