Shoutbox

well firefox is a small threat. in the terms of the number of home users that may change to firefox because it is easy to do. on a network it is much more difficult so a network administrator probaly wouldnt bother. and its them that firefox needs to impress. in the big scheme of things home users arent going to be able to do anything to help increase firefox usage on a big scale (as much as you might think you can).
for networks to change over firefox will have to become a lot better at being able to display all web pages. it doesnt matter if thats the browser or the sites fault. and ie would have to have some kind of big problem that would force people to change but i dont see that happening any tmie soon.
in summary, firefox does pose a threat in the home use area btu not generally.