Figuring out who's in charge and how to stick to the original mission of the exchange can seem an insurmountable feat. This is true of any neutral effort. If you expect your participants to trust you, you can't be seen as an ally to one particular entity. An electronic marketplace has to be flexible. A lot can change in a short period of time, and an exchange has to be ready to handle that change.
Participants have to understand the mechanism for change and be able to respond to it.
There must be a plan in place for resolving disputes. Members are bound to have disagreements. That's a fact. But not having a clear set of rules for settling disputes is what can bring down a business. There must also be clear rules on competition and the sharing of information so members don't feel they have been duped.