Fallout Tease?

Bethesda Game Studios tweets a "please stand by" message in the unmistakably duck and cover style of their Fallout series. It remains to be seen what comes of this, but E3 is on the horizon, so perhaps an announcement is in the works. PCGamesN notes a follow-up tweet from Obsidian where the Fallout: New Vegas developer indicates that this does not involve them, saying, "How do you let someone down easily? Asking for a friend. #ItsNotUs."