Interesting is that only a week before Zenimax registered The Elder Scrolls V: Hearthfire, they also registered the trademark DRAGONBORN (click for link to the trademark registration). While this seems logical, to protect words which are important to their franchise, the DRAGONBORN trademark shares the same description as Dawnguard and Hearthfire do, to be exact: Computer game software for use with computers and video game consoles; downloadable computer game software offered via the internet and wireless devices. Summed up, that says the registered trademark is a piece of software, distributed as downloadable content, also known as DLC. For the readers who still don't get what it says: the title DRAGONBORN is (possibly) a DLC.
So, perhaps we are looking at the third DLC here, The Elder Scrolls V: Dragonborn. Or maybe this is just a case of protecting a 'brand name' by trademarking it. If this is the third DLC, you know from whom you heared it first, Saratje! (Credit where it is due, mkay?).
Ofcourse, people may have noticed before that DRAGONBORN was a registered trademark. But now that Hearthfire is released (and is such a small DLC), this makes one wonder if DRAGONBORN is the title for a much larger DLC which may have been developed simultaneously with Hearthfire. Discuss and comment!