I feel that security will be the biggest issue in game. with many small security forces contracted to protect a certain player or small org, they will have difficulties banding together to protect against a large professional military entity. We need to make the marketplace as un-enticing for orgs to attack and control, how do we do that? If there are no market fees or transaction fees, and that is hardcoded into the marketplace the incentive drops considerably.
The best strategic move is to not take any fees or taxes which will attract a disproportionally large amount of players. The large amount of players will create a network effect, at this point you can make money off of all the players by providing optional goods and services. (rent, special quests for Myriad members, etc.). You it will be too inconvenient for players to go elsewhere.
Whoever saves the player the most time and hassle will win big. ((think amazon or Uber) both of which have only very recently became profitable companies.))
Don't eat apple seeds in winter, plant an orchard and enjoy the fruits of your labour forever.