Battlegrounds
As seen on the Official Blizzard realm types page.
In time, all standard servers will include a consensual Player vs. Player system called Battlegrounds. Once Battlegrounds has been implemented, players will have the ability to attack other players to defend their cities and towns from invasion. We expect the Battlegrounds system to be available later during the beta test.
This is an interesting concept for a MMOG. One of the biggest draws of DAoC and Shadowbane were their Realm Vs. Realm and City Sieging respectively. Blizzard appears to be implementing a similiar system in World of Warcraft. This type of PvP concept will bring a tactical and strategic level to the roleplaying genre. Not only will you be fighting players of the other faction, but you will be fighting NPCS as well as potentially having a base that you must protect. Perhaps this will be implemented in such a way that you will feel like you are playing just one unit in a "big game of Warcraft 3."
There are many options for the combat in such an instanced battlezone. You could do quests to build towers and forts, hire NPC guards, build seige equipment, or throw yourself out into the combat and use your own player's skills and abilities to directly influence the battle.
Some of the possible seige equipment mentioned thus far is
- Catapults
- Steam Tanks
- Warlock Infernals