So by now everyone here knows that Amon uses bloodbending to remove bending, but how exactly does he do it?
And I don't know if anyone else started this, or if this theory is old, I just watched the entire season in one sitting a couple of days ago.
My theory is that he uses bloodbending to permanently damage the chi points, preventing chi from flowing. It's an obvious theory and that's probably why they didn't bother to spell it out and why "Amon is a bloodbender" is the only shocking revelation needed.
I assume that the stances used to bend exist to assist people in using chi to suit their elemental affinity.
If Amon has the same skills has Ty Lee and the rest of the Equalist "ninja squad", which would not be pushing it since they are seen training in chi blocking, then he studied the point used in fire, water and earth bending. He defeats Korra by damaging those points. But he can't seal her airbending because he doesn't know which points to destroy or 'bloodtouch' if you will, seeing as there are only a 4 living airbenders.
But this theory has its problems. We never see Ty Lee chi blocking Aang, so I'm not sure if the points used and blocked are common or dependent on element. Also, Amon was going to remove Tenzin's bending, and I don't know how he was planning on doing it, by following my theory, since it would contradict him not be able to take away Korra's airbending before she could use it. So the question that needs to be answered is not "How does Amon emulate energybending" but "How could Korra airbend after having the other elements taken away from her". And that, well, I have no idea.