1. A computer-implemented method of selecting side information for use in interactive compression of data, comprising steps of: synchronizing side information databases at a server and a client; receiving a request for data, including a data identifier, at one of the server or the client; parsing the data identifier to identify constituent elements of the data identifier; searching the synchronized side information database at the one of the server or the client to identify entries in the side information database corresponding to the constituent elements of the data identifier; and selecting at least one unit of side information based on the identified entries for use in compressing the requested data.