Servers and critical mass

Eric from Elder Gamer says that an MMO dies when its population no longer reaches critical mass, and wants the EQ2 servers to be merged. The problem is that most games even in bad times still have "critical mass", only it is badly distributed over many servers, each of which is below critical mass. Or there is critical mass only for the most popular content. There are still enough players on any one WoW servers to get a group to Karazhan together. But there aren't enough to get a Gnomeregan run together. And with the typical summer slump coming up, on less populated WoW servers on the less popular faction it will be hard to find groups for many dungeons. The specific problem for WoW is that server mergers are probably not a good idea. Most of the absentees will come back for the Wrath of the Lich King, and then servers would suffer from overpopulation and queues if they were merged.

I'm not a tech guy. I have enough tech knowledge to install a new graphics card or RAM, or to network a printer, but I know nothing about servers and data protocols and stuff. But from a simple user perspective I have to ask: why are most MMORPGs divided into several servers? Why can't we all play together on one big single server?

Apparently it is *not* a problem of total server population. EVE Online has only one single server, with a quarter of a million players on it, and most of the time it is running fine (although the Empyrean Age seems to have caused connection problems). The problem in general appears to be server instability and lag if too many people gather at the same point. Even in EVE there are hubs like Jita, where bad things happen if too many people gather there. In World of Warcraft the opening of the gates of Ahn'qiraj caused too many players to gather in Silithus, which then caused server crashes and enormous lag. In Age of Conan siege warfare, where by definition many players gather at one place, are a buggy lagfest. Apparently when in a virtual world you go somewhere where there are many other players, data traffic goes up exponentially, because every one of those players needs to be informed of the movements of every other player, and the servers can't handle that traffic.

So I'm wondering if developers can't come up with a better system. I remember in Final Fantasy XI the data traffic simply was automatically throttled when you came to a crowded area. You stepped onto the square in front of the auction house and at first saw nobody, and then people plopped into view slowly, one after one. Of course that can't be a solution for massive PvP battles; but who says that I need to be instantly informed of every other player's action in Orgrimmar when I just want to use the bank and auction house? I think clever programming of the way data traffic is handled could seriously improve matters.

Another possible solution would be instances. World of Warcraft should have cross-server dungeons working the same way as cross-server battlegrounds already do. The majority of group content in WoW is instanced, so as long as you put in the same restrictions to trade that already exist in cross-server battlegrounds, why shouldn't people be allowed to find a cross-server group for dungeons that are rarely visited nowadays? In Age of Conan all zones are already instanced, I don't know why they also need to separate people into different servers.

The final hope is technological advances. Future servers might simply become more powerful and be able to handle more people. Right now the maximum population a server can handle isn't a large multiple of the "critical mass" Eric is talking about, so even normal daily or seasonal variations of the number of concurrent users mean that at some times there aren't enough people online for groups to certain destinations. If a WoW server could handle 10,000 players, there would be less problems when only half of that are online, because that would still be more than a full server now.

And maybe there are other ideas which could guarantee that a MMO always has more than critical mass for people to play together. If you have an idea, tell us!