1. A common directory comprising: a directory service logic; a search index storage unit adapted to store subscriber search keys of all subscribers in a network; and a local profile storage unit adapted to store profiles of a portion of all subscribers in the network, the directory service logic being adapted to access subscriber profiles by interfacing with said search index storage unit and with said local profile storage unit, the stored subscriber search keys being automatically replicated at remote search index storage units associated with other common directories, and wherein the stored subscriber profiles are not automatically replicated at remote local profile storage units associated with the other common directories.