Abstract: A new system for communicating between computer programs is disclosed which includes a collaboration software program having a directory publishing procedure and a message forwarding procedure. In an example embodiment, the disclosed system provides a user of a network application program, such as an internet chat program, with an out-of-band mechanism to send invitations to other users of the network application program. A user of the network application program requests a list of all users known to the collaboration software program. The user list is for example a list of user names associated by the collaboration software program with URLs of home pages of users known to or registered with the collaboration software program. The user seeking to send the message then selects a user name and provides a message to the collaboration software program. The collaboration software program then posts the message so that the message can be displayed in the home page of the selected user.