A system and a method are disclosed for providing telephone number sharing services to subscribers over public switched telephone network or data network. The disclosed system maintains a bank of reusable caller identifiers (IDs). The system receives call details of a call from a subscriber of the system. The call details include a caller identifier (ID) preference of the subscriber and a called number corresponding to the called party. The system stores the call details in a database. The system determines whether the call from the subscriber is a first call to the called number. In response to the call being the first call to the called number, the system assigns a call ID from the bank of reusable caller IDs that satisfies the reusable caller ID preference of the subscriber, and connects the call to the called number along with the caller ID.