1. A method for maintaining and sharing identity information, comprising: performing, by a computer: aggregating multiple types of identity information for a group identity, wherein the group identity is an identity that represents a plurality of other identities, wherein the aggregated identity information comprises communication-related information for each of the plurality of other identities, and wherein the aggregated identity information further comprises one or more preferences for controlling or restricting distribution of the aggregated identity information for the group identity; storing the aggregated identity information for the group identity in a single shared identity object as though the plurality of other identities were a single identity, wherein the single shared identity object is one of a plurality of shared identity objects each corresponding to a different identity; in response to a request to communicate with the group identity, accessing the aggregated identity information for the group identity that is stored in the single shared identity object, wherein said accessing comprises accessing communication-related information for at least one of the plurality of other identities; and modifying at least a portion of the aggregated identity information for the group identity in the single shared identity object.