After further thought, I see your point in Diablo not being an mmo.. The games player base can really only communicate in a massive way in the games hub as afore mentioned, and it's not like you get to see more than 8 people at one point in time(in the actual game I mean) . However, with guild wars it is possible to see the majority of players in a centralized hub, in a way that you are still interacting with them,(trade, conversation). So in the sense of an MMORPG, I think GW, although obviously not as mmorpg-ish as say FFXIV, or wow.. could still be considered an MMO..