Reckoning (US) »
Firetree is an EST US PvP server founded February 24 of 2005, among the first wave of new servers established after the game was released. Currently houses Pie Chart guild ranked as #13 in the United States.
Firetree consists of a great community, small enough so everyone knows each other, but large enough to house many great guilds.
For Facebook users you can find a growing community at 
Horde: Horde has, for a long time, struggled to maintain a unified position on almost any front. (With the exception of pre-rushing Alterac Valley in which Horde enjoyed superiority for years at a time using the Preform AV Enabler Add-On.) While they lacked a unified vision to go after dungeon objectives, they compensated with a fierce continual world and Battleground PvP presence that was never to be underestimated. When world PvP died out it was Ave Satanas and Smakaho Tribe that brought it back. With the drastic changes to game mechanics brought by the Burning Crusade (specifically 10-man raiding teams), Horde PvE progression has accelerated to unprecedented levels. Being able to work in smaller raid sizes, Horde guilds such as No Life and Pie Chart were able to become of the greatest guilds of the server.
Alliance side: Firetree’s community has maintained an enigmatic appeal that has kept many of the original players on the server for several years. In the very early days, many guilds reshuffled their power structures due to raid loot disputes and personal animosity, but nothing to the severity of Hordeside politics. Even amidst restructuring, PvE progression was still being done at an acceptable rate with a good number of Alliance guilds. Aside from the notable exceptions of the Chosen/Lucky Strikes/Arc three-capital assault (that crashed Kalimdor) and the Chosen/Lucky Strikes assassination of Thrall, Alliance world PvP has been sporadic at best. Alliance has focused on PvE in such detail that many advanced guilds offer pick-up spots for non-guilded members to partake in as well as offering them loot.
Mists of Pandaria
Community: As Firetree continues into the Mists of Pandaria expansion we can see many issues developing on the Horde Side. Many of the top raiding guilds have found it hard to maintain a solid raiding group. Many have fallen victim to their secondary raiding groups creating guilds that flop, copy their original guild names to trick people into their guild or other subtle things to bolster numbers. Trade chat is plagued by trolls of all ages (not just teenagers anymore) and conversations about anything not related to the game constantly drowns out an effective trade channel.
PvP: The PvP aspect has been plagued by almost every Rated Battle Ground being a full composition of Humans with Night Elf Druids. Being unable to overcome the extra PvP power/Resil that humans receive and the inability to effectively kill Night Elf Druids with their ability to macro their shadow meld/cat form/prowl and stealth midcombat and be able to heal to full and continue their push towards victory. What used to be on of the best PvP Horde servers in America has now suffered a great void of any organized PvP with a mass exodus of talented PvP players who used to be Horde going over to Human/Night Elf alliance to achieve their PvP goals and ambitions.