Talking of Firefox 3, there's a fascinating map that shows how many downloads have taken place so far around the world. Although it is only indicative, rather than rigorous, it does throw up some interesting trends.
For example, despite previous poor showings in terms of Firefox's installed base, the UK does not do too shabbily: currently, some 182,000 downloads have taken place, roughly comparable to France and Spain, although some way behind Germany. Poland is doing extremely well on 120,000. But for me the biggest (pleasant) surprise is Iran, currently on 177,000. Since when was Iran a hotbed of Firefox lovers? I'd love to know the background to this amazing figure.
Finally, on the downside, China clocks in with a rather miserable 120,000: given the huge Internet population of that country – to say nothing of its overall population – this is disappointing, and suggests that Firefox has a long way to go to convince users of Internet Explorer and Maxthon, hugely popular there, to switch. The Mozilla Foundation needs to make cracking the Sinitic nut a priority.