February - last edited February
Not much to tell really. There are 3 different auction houses. There always has been as far as I know. There used to be able to tell which one you were in by searching a certain player and by the buy now price of said player you could tell which one you were in. That's how I discovered I was in ah 2.
I know this is still the case because one of my admins is also in my ah so we can see the exact same players listed and other guys in my league see something else.
You would have to ask @EA_David @EA_Barry for more information on this.
Auctions are not player-to-player transactions, however the prices are indeed dictated by supply and demand from players.