Like my last post this for the people who dont follow everything about the game or have just discovered the game.
This is information I have read about since the PAX interviews, it may not be 100% correct or it may have changed or will change before the game is finished.
Once your character reaches level 10 you will placed in a Cyrodiil Campaign. You can think of a campaign as your very own Cyrodiil Server. It was said each campaign will hold around 2000 people. You will be placed in the same campaign that your guild is in. main purpose of being able to hold a guild keep or tower. this also gives the sense of a home for your guild, that you will defend and upgrade with resources. If you are not part of a guild their will be other factors that determine your campain.
Some people do not like the idea of campaigs because they think it will work like a random battle ground fight. this is not the case, not only will you be with your guild you will always see the same alliance guilds and players. You will also see the same enemy guilds and players. this will allow you to recognize your enemy and will start grudge matches and even revenge play.
It was said the campaigns will last months. The purpose of the campaign is to declare one side the winner of the capitol city and to declare 1 player the emporer. It has not been said how this will be determined. when a camapaign ends the map DOES NOT reset, keeps and towers will remain controlled by the guilds that had them. Which i really like because it brings back the feel of DOAC where stuff did not reset, the only way to lose something you controlled was for enemy players to actually take action and capture it. This gave much more importance in owning something, defending it, and upgrading it. The only thing that will reset is the score system of determening which side will claim the capitol city and who will be the new emporer at the end of the new campaign. the guilds involved in the campaign will remain the same. Players that had switched guilds will now be added to the new campaigns. So will new guilds if needed. Campaigns will be monitored allowing for balance among the alliances during creation. Depending on the game population campaigns will be created as needed.