Oh, I still shop the vendors all the time. When soe shuts it down, I hit as many merchants as I can, as when it comes back up, they all have new stuff, recently sold to them.
Farming merchants: They used to have more stuff than you could see, so lets say you bought a "rusty sword" that was showing, and a new item would appear in the last slot, let's say a high quality bear pelt, that you could not see before. There was more to it but that is the basics.