A living world is a persistent campaign world with multiple GMs running games at the same time within the framework of a consistant setting. Adventures and characters can go from one adventure to another within the world whenever they are unattached. Duplication Girl can be in an adventure run by DM A, and then when that adventure ends, join in another adventure that is just starting up.
Characters are approved for the campaign world so they are able to go from one DM to another without needing to be reapproved/recreated whatever.