Advantages
Application

for Users

for Web sites
Virtual Shopping See other customers and sales person. Sales persons notice customers entering a virtual store. Can talk to customers while they are there.
Web based CSCW See other online participants. Augment asynchronous collaboration with synchronous collaboration
Replacement for Chat Rooms Users are able to talk to each other on every page (unless pages are excluded by site operator). No dedicated chat software. Increased flexibility. Pages can be clustered to chat areas.
User Tracking Site operators can watch users browse the pages live. Icons of users move from page to page in a 3-dimensional site display.
Chance Meetings on the Web People, bump into each other on a Cobrow enabled Web site like they do in the real world, at real street corners, in shops, etc. Authors can be permanently present on their pages. Users  see them and can talk to them.