Battlegrounds are instanced areas used for player versus player combat. Each classic battleground (Warsong Gulch, Arathi Basin and Alterac Valley) has two red instance entrance portals: one for the Alliance, and one for the Horde. Crossing these portals was originally one of the ways to enter the queue for their respective battlegrounds. Now, to enter the queue for any battleground, the player must seek out a Battlemaster, which can be found at the portal or in any capital city, or do so through the Player vs. Player tab. Once inside the instance, the two teams will engage in large-scale PvP, with various objectives determining the winner. Players will earn honor points making PvP rewards available.
If a character goes AFK, he/she will leave the battleground and gain the Deserterdebuff. This prevents entry to another battleground for a 15 minute duration. You can report an inactive player by right clicking the player's portrait and selecting "Report AFK". When enough reports are registered, a 60 second debuff will begin to count down. Once the timer is up a new debuff will appear that will prevent the player from gaining any honor or marks while it is on. This debuff can be negated as soon as the player engages in PvP combat. This system is often abused, since a player can have good reasons for not participating in PVP, for example when he is defending.
Blizzard separates the various battlegrounds into three separate types:
Keep the resources flowing into the stores of your faction by capturing and holding nodes. Stall the enemy, disrupt their operations and you may soon be cruisin’ the road to victory.
Capture the Flag
Sneak into the enemy’s fort, take their symbol of pride (flag) and return triumphantly (means: alive) to your own flag. Do not allow the enemy to take your flag or you will be unable to capture theirs.
Ride into the fields of battle and clash with the enemy force. Burn down their towers, obliterate their defences and eliminate, or secure, high priority targets.
Originally slated to be an Alterac Valley style instance, this battleground was far enough along in development that there were even Horde and Alliance entrances in Azshara. It never saw release, however, and with the zone overhaul in Cataclysm removing the physical location in which it would have existed, its fate seems to have been sealed.
A "deathmatch" style battleground, it was scrapped early in development but the concept eventually turned into Arena PvP.
XP in Battlegrounds
Blizzard stated that XP for playing in the battlegrounds has been added in Patch 3.2.
Slahtz and Behsten are the NPCs that can eliminate your experience gaining for a 10 fee should you decide you want to stay a certain level in the battlegrounds. Note that turning off xp will do so for all sources of experience, including quests.
In Patch 3.1.3, Alterac Valley (AV) you can earn XP by killing mobs, however the XP gain is very low if a lot of your faction players are within range.
By glitch or by design, XP awards were increased to move twinks to next bracket quickly, but Call to Honor weekend play still acts as a multiplier of this increased amount, allowing the player to add one level in as little as three wins. Players that know this can use PvP for leveling. Example: Level 42 to level 47 was done on a Sunday in about 5 hours. Incredible XP! :)
β Patch 5.0.1 (Beta): New battlegrounds added. Ability to blacklist some battlegrounds fromt he queue.
Patch 4.0.3 (15-Nov-2010): New Battleground Level Brackets.
Is the way we queue for Battlegrounds changing at all? Tom Chilton - Yes, we’re adding a way for players to down-vote two Battlegrounds that they don’t want to see show up when queuing for random Battlegrounds. The exception to this is if it’s the Battleground featured with Call to Arms. You won’t be able to down-vote those when they happen, but this should make it so that it’s less likely you’ll be taking part in a Battleground that you don’t particularly enjoy. It should also help make it more likely that when a particular Battleground comes up on the Call to Arms, you may be able to enjoy it more. We’re also changing the way Call to Arms works so that there will always be a Call to Arms Battleground available. This will allow us to cycle through a larger amount of Battlegrounds on a regular basis.