Online games usually get boring, once you have levelled up your hero or built all the buildings you can, you have nothing left to do except attack other players or produce massive amounts of resources.
This is primarly based on the standard model, where things get more difficult to do as you progress. Not in terms of skill, but in time and resources. To shorten the time, or lessen the resource requirement, you need to spend money for game coins.
These economies are over simplified and crude, which prevents any complex relationships evolving in these online worlds. Your contract is between you and the game company, with only the occasional game allowing players to earn game currency within the game.
It seems to me that there is a lot of scope for these games to become a trading place for different services offered by the players. This could be the creation of fine virtual items based on an expensively acquired skill, or it could be for a real world service. For example, a bar owner might sell a pint of beer in their bar for 20 game coins.
Malls were created to increase the overall amount of customer spend in that location, i.e. if the customer needed something they would get it at the mall, rather than drive somewhere else.
By creating virtual economies, we can drive community behaviours, where trust and a sense of belonging or perhaps just convenience leads people to buy things from the 'Guild Mall' rather than an external organisation.
Think of it as a merging of Shopper clubs with WoW.
Whether the scenario is quite as complex as that, we will have to wait and see, but this year should be the year where online communities start to have influence in the real world and potentially start to disintermediate the corporate and government bodies.