The Four Elemental Clans/Nations play a large role in Expedition into the Mists.
Resources can be traded amongst clans. There are several restrictions on what can be traded, however.
Trades are processed with each tick.
Trades can only be made with the amount of resources that a clan generates from Resource Nodes with each tick, not with a clan's current resource pool.
You can currently only trade resources that your clan generates itself - for example, you can't re-trade resources you are receiving in a trade.
Proposing a Trade Agreement
If a clan wishes to propose a Trade Agreement with another clan, a clan member may do so from the Clan Trades page. This will send a notification to members of the other clan, who will have to review and accept or decline the proposal.
After the agreement has been accepted, both clans will start gaining/losing their selected resources starting from the next tick.
Cancelling a Trade Agreement
Cancelling an agreement is as easy as clicking the "End Agreement" button on the Clan Trades page.