1. A method for using a source deduplicating store to update a target deduplicating store with information representing how data objects change over time, said method comprising: at the source deduplicating store, for each data object, creating an organized arrangement of hash structures, wherein each hash structure includes a hash signature for a corresponding content segment and is associated with a reference to the corresponding content segment, wherein a logical organization of the organized arrangement represents a logical organization of content segments as they are represented within the data object; at the source deduplicating store, for each data object, maintaining an organized arrangement of source temporal structures to represent a corresponding data object over time, wherein each source temporal structure is associated with a temporal state of the data object, a logical arrangement of source temporal structures is indicative of changing temporal states of the data object, and each temporal state is associated with a set of hash structures representing all content of the data object that has changed relative to a prior temporal state; for each data object, maintaining an organized arrangement of remote temporal structures representing corresponding data objects stored at the target deduplicating store, wherein each remote temporal structure corresponds to content segments previously transmitted to the target deduplicating store; in response to a request to update the target deduplicating store with information from said source deduplicating store, finding a temporal state common to the source and target deduplicating stores using the organized arrangement of remote temporal structures, wherein the found temporal state is a state known to be stored at the target deduplicating store and known to be a nearest neighbor of a current temporal state; and compiling a set of hash signatures for the content that has changed from the common state to the current temporal state of the source deduplicating store and sending that set of hash signatures to the target deduplicating store for updating the organized arrangement of hash structures to represent the content of the data object up to the current temporal state of the source deduplicating store, wherein, after the requested update, each of the source and target deduplicating stores includes representations of the data object indicating how the data object has changed over time.