I agree with my fellow American, Phil M.
If a web application is written in English, any kind of English, be it the American or International version ( I believe the same British spellings are used in the U.K., Canada, Australia, S. Africa, etc.), then it should indeed not be assumed that the majority of users are from the U.S., but it IS reasonable to assume that the majority of viewers/users could be from any English-speaking country. So, put all natively-speaking English countries at the top of the list, in ALPHABETICAL order, followed by the rest of the world. Ok, throw in India there as well. English isn't exactly native but everyone who's gone to college there knows it well. Yes, I think it's arrogant, too, to put the U.S. at the top all the time.
As for spellings, I could have cared less when I was younger, I knew both ways and read both interchangeably, U.S. spellings or U.K., however, the longer I'm in I.T. the more I wish our schools would just teach both as being equally correct. You can thank Noah Webster for any I.T. application English-spelling headaches. Before that there was just one world standard, or pretty close.
The change in spellings was his idea to "standardise/standardize" the language: he really did no such thing, and in fact did the opposite. But then, I guess he lived in the 1800s. No web then.
