When I teach about late antique history, I want my students to have a sense of geography. What they get is me coming into the classroom one day with a rolled-up map of the ancient world, printed in 1960, over my shoulder. It is too small to be read more than a few feet away. I lecture, pointing to blobs of color and wondering just how clearly they know what I mean by "Po Valley". Can this be improved? Undoubtedly. How? Look here at two resources already on the WWW: the U.S.-Mexico border, from a server at Texas A&M that gives comparable justifications of visual and topographic representations for units this size of the whole U.S.A.; or else experiment with the Xerox Palo Alto Research Center map viewer, which lets you zero in on any coordinates on the globe with a little practice.
Would these resources be an improvement? Obviously. Not least because students can pursue assignments on their own with them, using them as flexibly as any atlas. But my point here is that with the technology in hand now, we can do vastly better. If we had classrooms that reliably assured me I could use a visual WWW-browser in class, it would then be worth my while to scan existing maps, make maps of my own, experiment with overlays, download specific satellite photgraphs from servers (I'd like to show my students Italy in color from space, once in January and once in July -- the change in colors says more about the ecology of that peninsula than any half-hour's lecture could convey). The WWW itself provides tools; but it is -- considering the power and repeated usefulness of them -- astonishingly easy to make tools of our using the same facilities.
The principle is broadly transferrable. It is now possible to use more and better customized visual materials in class, and at the same time to make them available for students to study outside class. No longer need History of Art, for example, manage a "picture study" room with all the questions of quality and security and facilities that arise there; a WWW exhibit may not have images of the highest quality resolution yet, but it is accessible 24 hours a day, with supporting text as well as images. Those of us in disciplines that have not used visual materials as vividly and well as we would like may, indeed should, review our practices and think how we can draw together more abundant and interesting supporting materials for our teaching.