There is described herein a message forwarding system that is easily adaptable to evolving technologies. In one embodiment, a first user attempts to place a telephone call to a second user, and caller identification (CID) data are encoded into the outgoing call. The call is directed into a public switched telephone network (PSTN) servicing the second user. The PSTN may operate on a modern telephony protocol such as Signaling System #7 and may be equipped with an Advanced Intelligent Network. If the call is not completed, a message including CID information is sent via means such as short messaging service. Because the equipment resides in the PSTN, it is independent of the technology used to receive the transmitted data. Furthermore, the information may be provided even in times of emergency, such as when telephone service to the second user has been disrupted.