A method for communicating real-time to subscribers of an Internet service provider, without requiring installation or set-up of client software by the subscriber, utilizing unique identification information automatically provided by the subscriber during communications to provide a fixed identifier which is then examined in real time. Messages may then be selectively transmitted to the subscriber. The system may be transparent to the subscriber, with no modification of its content along the path identified by the subscriber. Where desired, content may be modified or replaced along the path to the subscriber. The system forces the delivery of information to the subscriber for the purposes of establishing a reliable delivery of bulletin messages from providers to their subscribers. These messages may be displayed permanently, temporarily, or in separate pop-up browser windows, according to provider preference.