Long time lurker of these boards, but I decided I want to post a theory I had in regards to Crowley, Sam, and Purgatory. Hopefully it's not too terrible.I'll foreword it by saying that I don't believe Crowley brought Sam up because I think he doesn't have the juice (if Lucifer and Michael can't break out, that would make Crowley damn near all powerful, and so why would he need hunters to find alphas?), and Crowley also isn't the big bad of the season. I'll present my theory in sort a chronological order of events
1) Sam was brought back out of the cage by something we simply don't know about yet (someone mentioned that it might be the creator- or "mother" as the alpha vamp puts it- of the monsters). The reason I think he doesn't have a soul is that this was part of a deal he made to get out. I'm not sure what this "thing" would want with souls, but Balthazar mentioned something to the effect of "You don't know the value of a human soul." I suspect we'll learn a development about human souls soon enough.
2) Crowley, being the newly crowned King of Hell, senses that Sam has somehow been pulled out. Using his quick wit, he cleverly deduces that it must be something on the monsters side (since the two biggest forces on Heaven and Hell's side are in the cage, that really would only leave the "mother"). He decides to pull down Samuel because he knows that Sam will listen to him, and because Samuel knows so much about monsters. I like the idea that Samuel is doing this to bring back Mary and/or John, too.
3) Now, I'm thinking Crowley wants to find Purgatory so he can deal with this "mother" before it is too late, since "she's" clearly extremely powerful. But also, I don't think he's telling Samuel or anyone this because he possibly wants to use "her" to take over Heaven and Earth too, and that's a plan I'm pretty sure no one would agree to. I don't really buy the whole expansion of Hell since I think it more than stands reason to believe Hell would be infinite in scope.
I'm not really sure where the war in Heaven would stand in all of this, but you've got some of the most powerful beings fighting eachother while the monsters are preparing for war? I think that's by design instead of by accident.
So I hope that wasn't too crappy of a theory, hehe. I'm open to this being plucked full of holes and any criticism of course.