Last time I posted about my guild's stronghold, we still seemed to have some ways to go to unlocking our second building. However, my pet tank decided to plunder his old main's campaign currencies (since he switched to playing his paladin as his main) and apparently that was enough to push us over the edge. (I still suspect that there were some real money purchases involved somewhere...)
So now we have a farm, which produces food, which in turn serves no other purpose than to power the creation of even more stronghold buildings.
The next building however is the one that really interests us: the market. I don't think the NPCs there will sell us anything interesting at level one, however just having a vendor inside the stronghold would be nice, as a lack of somewhere to sell things has been the one major drawback of using the stronghold as a hub so far.