I find it fascinating that anyone in the US has this issue, as a Brit this was an issue for anyone with early internet exposure, but I hadn't considered the volume of British/Canadian/Aussie English to have an impact the other way round!
I remember in the 1980s entering a computer program into my BBC Micro after watching The Computer Programme[1] and finding out that it had dual spellings of key words like COLOUR/COLOR in its BASIC.
So even before the internet was widely used people in the UK we’re aware of the problem.
> as a Brit this was an issue for anyone with early internet exposure
Same here as a Swedish person who grew up with American media + eventually getting into Internet communities. English exams felt great when I took them, I knew all the answers after all.
But then getting the results back was always disappointing, as Swedish schools teach "British English", not "American English", so you better use the British spelling and pronunciation, otherwise it's completely wrong obviously and you deserve punishment.
Companies, for example, have very detailed style guides about usage to enforce consistency. Obviously we don't "punish" people for doing things differently but we do correct them and, by implication, ask them to do it differently next time.