Alex Burmaster, European Internet Analyst at Nielsen//NetRatings explains:

Whilst IE still dominates the web browser space, and is likely to do so for some time to come, the growth in take-up of Firefox shouldn't be ignored. Aside from its supporters' claims of its superior security and functionality, the open source nature of Firefox and its competition with Microsoft has a huge appeal to those who believe in the egalitarian and participatory ethos of the Internet. In other words, Firefox represents, for many, Web 2.0 and IE Web 1.0.

For more details, you may download the Word document from the NetRatings.com Website, with graphics and more information:

Britons who use Firefox as their main browser average 28% more time online and view 41% more web pages than the average Internet Explorer user. Firefox users spent an average of 24.4 hours online in September – browsing 2,070 pages – compared to 19.1 hours and 1,473 pages for the average Internet Explorer user.

As a reminder, XitiMonitor report for end of November 2006 mentions that 15.8% of visits to Websites in the UK are done by users with Firefox or one of its derivatives. (33% in Germany, 33.6% in Poland, 39.3% in Finland, 40.5% in Slovenia !) The European average is 23.2% and shows steady growth:

Firefox use rate in Europe

Firefox use rate in Europe (source: XitiMonitor.com)