A quick analysis of the top ten user agents in the https://bluedonkey.org statistics seems to suggest that not many people have actually installed Microsoft’s Windows XP SP2. My top ten real browsers (i.e. excluding search engine bots) for the first seven days of October fall out like this:

All the top ten real browsers were running on Windows machines. The first non-Windows entry was for MacOS X, but not running a browser; instead, it was the NetNewsWire RSS news reader software from Ranchero Software. Linux appears in third place in terms of OS share (though it is pretty close to MacOS X).