Systems and techniques for transferring electronic data between users of a communications system include a host system structured and arranged to receive and deliver messages of various types between users of the communications system. The host system includes an instant messaging network; a mail gateway; and a configuring network in communication with both the instant messaging network and the mail gateway. The instant messaging network enables instant messaging communication between users of the communications system and has the capability to monitor whether a certain user is capable of receiving an instant message at a particular moment. The mail gateway receives and delivers e-mail messages to users of the communications system. The configuring network is dedicated to automatically configuring instant messaging communication between an intended recipient of an e-mail message and the sender of the e-mail message.