So there you are, slaughtering innocent bears, and one of them drops an item called Waylaid Supplies: Copper Bars. What could this be? I'm glad you asked. As the conflicts wage on, both the Horde and the Alliance have established supply networks to get their troops what they need when they need them. But there is a problem; it's not just bears and Copper Bars, shipments of all types keep getting waylaid and supplies are going missing. Durotar Supply and Logistics (Horde) and the Azeroth Commerce Authority (Alliance) will pay good money to get their shipments back.
But there is more. When you find these shipments, inevitably there is stuff missing. So here is what you do: you can return that shipment to a DS&L or ACA representative as-is, and get a reward, or you can make up the missing goods from your own supplies and turn it in for a better reward. It's your choice, but don't underestimate the power of the good will of these organizations.
Durotar Supply and Logistics Guide Azeroth Commerce Authority Guide
In return for these shipments you get a little silver, some experience, and Reputation. That last item is what you are after. Once you reach Friendly with these factions, they will allow you to buy from them. And when you reach Honored, you can buy Runes, including Rune of Teasing which is necessary for Rogue Tanks. These little beauties will only cost you apiece:
So be patriotic, do your part, and you too will be rewarded.