We study the communication complexity of rumor spreading in the random phone-call model. Suppose n players communicate in parallel rounds, where in each round every player calls a randomly selected communication partner. A player u is allowed to exchange messages during a round only with the player that u called, and with all the players that u received calls from, in that round. In every round, a (possibly empty) set of rumors to be distributed among all players is generated, and each of the rumors is initially placed in a subset of the players. Karp et. al [16] showed that no rumor-spreading algorithm that spreads a rumor to all players with constant probability can be both time-optimal, taking O(lg n) rounds, and message-optimal, using O(n) messages per rumor. For address-oblivious algorithms, in particular, they showed that (n lg lg n) messages per rumor are required, and they described an algorithm that matches this bound and takes O(lg n) rounds. We investigate the number of com...