Perhaps not for everyone, but on steam status page it shows as down, and can only launch steam client in offline mode.
Which since ESO requires steam authentication now, means ESO is down as well. Not blaming ZOS per se, as this is a steam issue - and personally it's rare steam is entirely offline/down. But in the age of digital licensing, since we have to register with ZOS regardless which source we bought the game, it would be nice if we could login/authenticate using simply our registered login - which of course ZOS knows precisely what we bought, etc.