Re: 1. I wouldn't even have thought it was accessible cross-browser. So I did some googling.
Peter states he was told it uses html5 local storage:
And I found this stackoverflow post, which seems to confirm it's per browser only:
I'm not an expert though, so I'd be happy to be proven wrong.
I can't help with the second issue. The HTML5 local storage topic linked in Peter's post suggests it should be available for IE8 and above.
But I just had a thought. If your IE version is set to compatibility mode (I think intranet sites can be set up that way) then you might not have local storage. Oh, and I think it's not available when running locally, so make sure you test on a proper web server.
Just to add to Amber's excellent comment, here is an excerpt from Willam's blog
"...Saving a page as a favorite saves the pages in the browsers’ cache. And the help system has a list of all favorites within the current project. ..a single click adds the list to the favorites. Favorites survive a reboot and are only removed when a user clears all browser history and cache:"
Also, for convenience here is the relevant link to Peter's summary on Favorites.
Adobe Certified RoboHelp and Captivate Instructor
Ahhhh, isn't the world of browsers and all that rot just wrought with fun? (I jest)
Another thing to consider on this is that in today's brave new world of browsers, it's possible to configure your browser to "forget" everything when you close it. So if the favorites have been stored this way, it seems only logical that if your IE browser has been configured to "forget" the browsing history, the favorite won't appear next time you open IE.