Here's another link for you:
http://www.usdoj.gov/opcl/1974definitions.htm#agency
Now, as to who to believe, you or the Department of Justice I think I'm going to lean towards the Department of Justice on this one.
Edit: I think it's hilarious that you "lol" a DOJ legal opinion but expect your personal legal opinion to be taken seriously.
And it's not that I reject anything you say out of hand. It's just that when you say something that doesn't make a whole hell of a lot of sense (the White House is required by law to keep all its mail and email but can't because it is prohibited from doing so by law, lol) I'm not simply willing to take your word for it. And you haven't really backed up what you are saying at all.
I also think it funny that you criticize me for rejecting anything you say out of hand while you reject pretty much anything I say out of hand even after I provide you with the legal analysis that supports my position (something you rarely provide).
My guess is that this will be resolved by the Courts. If the birther nonsense has taught us anything it's that there is no shortage of lunatic right-wingers willing to spend money on frivolous lawsuits.