Providing online forums and bulletin boards for transmission of messages among computer users concerning classified listings and listings for announcements, events, concerts, classes, class management, meetings, activities, housing, real estate, roommates, rentals, for sale advertisements, services, and information on a wide variety of topics of general interest to the public; providing on-line forums and discussion groups for transmission of messages among computer users concerning arts, leisure, entertainment, classes, class management, work, and information on a wide variety of topics of general interest to the public; electronic mail subscription services; and electronic transmission of messages, data and images