I have played since 2 months after launch, and the first I had ever heard of it was in Strat the other day with my girlfriend's 52 hunter. She tagged the courier, so I killed it. She picked up the keys and proceeded to open the mailboxes as we went by them. I kept pulling the elites off of her and on the third time, there was the postmaster. I looked at the set piece and saw the other 5 and just went, "...huh."

Total news to me, hehe....

Don't forget about the T.5 [Tier point five] from the long, irritatingly expensive and grueling quest chains before you typically had access to actual Tier 1,2,3 pieces.
As a shammy I did the first three parts i think it was, to my Tier point five set and the quests took me all over the frikkin' planet and back and required expensive mats and ammounts of gold from what i remember. The only fun part about it was that during the turn in of the last part of the chain that I got to, the quest giver spawned a wraithlike mob you had to fight and kill and it so happened the first thing the wraith agroed to was a lvl 9 standing nearby, who got himself immediately one-shot by my quest mob..0.0 ahahaha!!!. I coudln't help but chuckle and afterward offered to rezurrect the poor victim of said wraithlike mob.

If you played a mage in Vanilla you knew about the Postmaster. Like the article says he used to drop a Magister's piece. Other than that there was no real reason to kill him. I'm not surprised people have no idea that he exists.