Thanks everyone. It is pretty simple afterall (and a great feature that you can see the history of the tab being viewed), oh, How I wish I had one of you nearby to ask in person!
I've emailed Jon Udell to ask how he did this:
http://weblog.infoworld.com/udell/gems/umlaut.html - but haven't got a reply.
I'm not very techy oriented and I am sort of alone in these studies up here in copenhagen, so, maybe someone knows how to do an equivalent thing (or point me for the start) - how to record frame after frame from history (now I know what pages to look for - but how to make it movie'ish?!). The idea is that, although History Flow can well show the changes, it is difficult to get a good grip - looking first at a movie would/could give a lot of insight. Also, for public presentations - would be nice to have some easy movies to show what is happening.
Thanks!
Best,
Rut