Web presentation in conjunction with a line of communication this is ideal for unstructured/adhoc presentations. The presenter has control of what the audience is shown and when, to within a defined time interval (a matter of seconds). Presentations can be performed where web access is available, note available web access can be the public internet, LAN, WAN, VPN ...
The way the presentation works is by a controller web page that when loaded opens up a child browser window (which is given main focus so the controller page sits hidden in the background). The controller page will then load the url (set within the controller page) in the child window. Since the controller page is defined to refresh every 5 seconds all the presenter need do is change the controller page to point to a new url and within a few seconds their audience will see the new site. Simply put, this is your own little overhead projector.