Originally Posted by Frosstbyte

Yeah, Icecrown in particular is INSANELY phased. It's probably a good place to quest because it will prepare you for Cata questing (which is equally, if not more, phased).

You really have to start at the beginning and progress through step by step. It makes for much more immersion in the storytelling, but it's much more restrictive in how and where you spend your game time.