Looking at the tags, we have a few inconsistencies between British and American spellings. For example, we have colour but also color-management, color-correction, and a couple of others, plus organisation (4x) but not organization.
Now, consistency would be nice, but if we pick one or the other, the site becomes less accessible to whoever wasn't picked, and it seems a shame to perpetuate American imperialism without good reason.
I think it's pretty certain that Americans are the largest constituency here, but do they outnumber the variety of English speakers who use British spellings? Is there any way to figure this out?