What server are you on? Don't answer; I don't care. I'm not sure you should either.
Servers used to mean much more. They were small towns. They had that small town feel of everyone knowing everyone and people being so bored that they'd start using meth/rep grinds.
We all knew each other to some extent. Not friends, but names got around. We knew who was a jerk and who wasn't and who made the best pre-mades which of course you couldn't get into. We had rules about what the honor cap was for the week and if you broke it we figured it out and shunned you. We even knew the other faction because we saw them every day in the BGs and out farming. The world's changed and the small towns are dying.
These are not intended to be in chronological order.
Cross-server battlegrounds were a major blow. PvP was no longer against the people you always saw. It wasn't 3000 vs. 3000 anymore, it became ten times that number. You wouldn't remember all the names before, but you would recognize them; not anymore. The rivalries went away.
Arenas took it further. No longer were you representing half your server against the other half, or even half your battlegroup. You were torn away from your faction to fight a thousand other teams. You would have rivalries between teams, but they weren't community.
Server transfers took it further. You were no longer so tied to your server to live and die there. With a few clicks and some cash, you were somewhere else. You could reroll before, but that was a much longer process, a much higher barrier to movement. Rerolling didn't allow you to carry with gold and materials. The transfer of a particularly wealthy player can completely disrupt the economy as they start to unload mats and put their gold to work getting more of yours. An entire guild may move, shaking up others as people jump back and forth between guilds as the progression rankings change.
Even the way we farm is changing servers. We used to all be on the same level: the ground. We were often farming an area rather than a resource: I'd see people grinding in parts of Silithus rather than flying loops around Sholazar. Back then we'd actually group up to farm; you had to to get through the silithids at a reasonable pace even though they could be soloed. This is part of the overall shift towards more and more solo play.
Now cross-realm LFG is coming. Server will no longer matter even for heroics. Raids are all that remain. I wonder how long for even those.
Someday we might see battlegroups as we used to see servers. Maybe they will be the new community, just much much bigger. I don't think it will be the same though. Humans can only interact with so many people before they start closing off any extras. At best I see servers being neighborhoods within a city, but not so much communities as ghettos; people trapped in their location even as they try to interact with the rest of the world.
I don't mean to sound so gloom and doom. There are benefits to the changes. That's why they were made, after all. We can get into BGs faster, we can get into groups faster, we aren't stuck on dying servers. But something is still lost. Community is weakened and dying servers are accelerated as people leave them rather than having a stake in them and a reason to save them.