A first processing session is entered with a POP client. A set of messages from a message repository is identified as available for access by the POP client. When the POP client causes a message to be deleted from the message repository (either by explicit or implicit actions), the message is removed from the set of messages available for access by the POP client but maintained for access by another POP client or by another messaging program. The messages available may be limited by a session size and they may be ordered newest to oldest. In some instances messages are part of conversations and the number of conversation from which the message may be drawn is limited.