Tuesday, June 10, 2003 01:40 PM
"Placeware" (not free) is a system for conducting training, conferencing etc., that does something like you describe (I'm just a user, haven't dug inside it) ... I can see that it uses a Java applet on each conference participant's desktop, which then displays what the instructor/leader is doing (like paging through a Powerpoint, viewing live Web pages, etc.) on their desktop, plus gives access to supplemental stored material etc.
Unfortunately it doesn't sound like a very "simple" feature, to me.... I used to know Ph.D. researchers working on similar, though more complicated, things (e.g. especially it gets more complicated when adding delayed playback, emailing back and forth, and adding/overdubbing layers of annotation, as in http://www.scr.siemens.com/pdf/spie94_1.pdf) ....