Elder Scrolls Online's NA megaserver was down for the better part of today for "inventory-related issues," although these have been addressed and the game is back up and running after over 12 hours of work. The devs pushed out a small patch when the server came back up that fixed various issues, including broken quests that blocked player progression.
It also appears that guilds have been neutered for the time being: "All guild functionality has been temporarily disabled. We will notify you when it has been turned back on. When guild functionality is returned, all guild-related tools and functions will be as they were before we turned them off."
One bright spot for the day is that the Elder Scrolls Online soundtrack is now available on iTunes.
[Update: ZeniMax just announced downtime for the EU megaserver.]