The new "1 day to go" countdown trailer contains a possibly big spoiler! If you don't want to glimpse what might just be OBLIVION itself, do not watch it!
I watched it and I regret it.
PS: Yes, I know that there is a spoiler section in the forums, but this isn't exactly a spoiler, it's more of an anti-spoiler.
I'm sure that, by now, most of you know that all of these "major spoilers" (including the quest log spoiler) aren't very major at all.
**Spoiler (obviously)**
You find out who the heir is, where to find him, and even talk to him pretty early on. I closed my first OB gate at level 1. They didn't release anything that wasn't newbie stuff.