Destiny DLC packs have been verified by Bungie Community Manager DeeJ in the Destiny forums. Some players this weekend hit an in-game glitch that revealed information about two DLC bundles, The Dark Below and House of Wolves.
"We noticed that you noticed that we already have plans for upcoming content packs in Destiny," DeeJ writes. "We do! They have activity names (which may or may not change) and we have a really good idea what they're going to contain. They even have placeholder nodes in the Director, as you've already discovered. But neither of the Expansion Packs we've announced are finished."