That Guy on 01 June 2008
de-facto means most commonly used.
HD-DVD may have come first, but Blu Ray came along and was more commonly used, so now its the de-facto standard in the english language =))))
Likewise, zed may have come first, but now there are more zee speakers 
I cannot speak for other languages, so if its pronounced Zed in dutch or french or whatever, then more power to you!
