Thanks, Morchai!
....lulwut.
Of course you defeat Alduin at the end,how is that a spoiler? That's akin to saying, at the end of Oblivion, you defeat Dagon. These are world ending events. They're not going to kill their own franchise early.
That's a poor anology on both sides, but primarily on the Oblivion comparison. When you start Oblivion, you don't really know you'll have to battle Dagon, now do you? You have to realize that not everyone has the foreknowledge you do. To you, this is not a spoiler. To people that never player Oblivion and are new to TES, it certainly is a spoiler. incidentally, the player does not defeat Dagon in Oblivion, anyway