Serving
different content from the same URL is generally a bad thing.
No, it’s not. That’s the reason they invented Language-headers in the
first place: So you can view a page in your language and I can view a
site in my language. Please respect that not everybody can read english
I think the context was that language headers are one way to solve that
problem, but with hindsight they are inferior to the solution of the
language being in the URL.
Caching is a very important practical reason. Just as important, for me
at least, is that if the preferred language is part of the URL I can
forward a URL to someone and be sure we are looking at the same content.
Generic pages that use the accept-language preferences to redirect to
the correct page are one possible way to please everyone. E.g.
wikidata.org could redirect to
en.wikidata.org or
de.wikidata.org or
ja.wikidata.org. But those redirects create extra load/bandwidth, and it
might be too late for it now (i.e. if millions of
wikidata.org URLs are
out there in the wild).
Darren