Ask HN: recent changes to character encodings on the web?

I visit a lot of sites written in languages which require characters which don't exist in the English alphabet. Back in the 90s and early 00s this was slightly problematic, since these special characters would often show up as gibberish. Then there was a long period between (roughly) 2002 and 2009 where shit Just Worked - one might even call it the Pax Typografica - but lately I've noticed a regression to the bad old days of the 90s. I might see an "Ä" being rendered as "ä" four or five times a day now. During the Pax Typografica, this was unheard of.

So, what's going on? Has the Unicode Consortium fucked up? Bugs in the latest versions of Firefox (my browser)?