Jakob Nielsen has an interesting little item in his Alertbox column on when it is appropriate to use British or American spelling on a Website. He makes some interesting points, such as the fact that no one buying, say, a Scottish kilt, on-line is going to be offended by the use of U.K. English, whereas no one booking into a Las Vegas hotel is going to expect the language to be other than U.S. English.
However, Nielsen misses a point and that is one relating to national culture - UK sites, it seems to me, should use British English, not U.S. English. I am offended when I find that long established British publishers publish books and journals with U.S. spelling. Our spelling might be idiosyncratic on either side of the Atlantic, but in both cases, they record the history of the language, which is part of our related but separate cultures.
This is why Information Research uses U.K. English, which is extended to ensuring that colloquialisms are converted to standard English and why jargon and allusions of individual, national relevance are removed. This may well be one of the reasons why readers frequently comment on the readability of the papers in the journal - we know that a significant proportion of our readers do not have English as their first language - or even their second - and we also know that about a third of our readers are non-academic, for whom the arcane language of a discipline would be a barrier to understanding.