Take from that what you will, because what it means is anyone's guess. The little concrete information in this trailer is that the game will soft launch in Canada and Australia before facing a wider release, and that it's going to be "epic."
However a possible clue was spotted by Angry Birds Nest (via Pocket Gamer) in a video Rovio posted in late 2013 that teased what the company has in store for this year. That video briefly features the image you see above, in which familiar Angry Birds characters are silhoutted dressed as a wizard, a warrior and an archer.
So if I had to guess I'd say there's a fantasy-themed Angry Birds game coming. After the sci-fi themes of Angry Birds Space and Angry Birds Star Wars that might be a nice change of pace—though on the other hand the Rovio series would be walking a fine line by getting even more similar to the older game Crush the Castle (Angry Birds' original, ahem, "inspiration").
Anyway, it's further unclear whether this game has anything to do with the Angry Birds Stella game that Rovio teased in February, though I'd bet that they're separate.