http://wiki.guildwars2.com/wiki/World_versus_World pitting 3 servers together in epic combat
http://www.guildwars2guru.com/forum/...ei-t24989.html more hype on it
What Omlech posted about it earlier:
Indeed, Wintergrasp can hold 240 players, each map in WvWvW can hold 666 players (as of now) and there's 4 persistent maps that are going at the same time totaling 2,000 people at once. Three servers are matched up against each other in an epic 2 week battle with keeps and siege weapons, dynamic events that affect the world and create conflicts. There's content for all group sizes in WvWvW too, say your guild holds a keep and there's a mine nearby, a group of players could go in and take the mine, a solo player could then escort the mine cart, and a guild could hold the keep. So say a dynamic event kicks off to escort a minecart from the mine that your server has taken. So people on your server would see the event to escort the minecart while the other 2 opposing servers would get a prompt to take the minecart back from you. If you get the minecart to a nearby keep, you could then start building siege weapons. However, if your enemies kill you and take the mniecart and then the mine they'd then probably be able to start pushing the minecart to their keep (theoretically if this is possible) and then they'd be able to build siege weapons. So there will be keeps that guilds can hold and fortify through a Guild based currency called Influence, beyond that the Dynamic Events will facilitate PvP in areas outside of keeps and other key capture points.
That's the non-serious pvp. It's perhaps the more innovative side of it.
Structured pvp is even more intense.
http://wiki.guildwars2.com/wiki/Structured_PvP
Hope that answers some questions