A typo for PMG. Which is a typo for OMG. PMQ doesn't mean anything, really. It's used to mock n33bs and make fun of un-1337 people. Most people use it to make fun of people, and show how dumb they are, by using a degrading acronym such as PMQ.
pmq wai y00 be haxin in mah css serveri r ban u nigar pmfq
You were SO bored that you typed out all the possible combinations of the letters on the corners of your keyboard.
Congrats your boredom has peaked!
You probably have important homework due, yet you would rather do this because anything is better than homework.
pqzm pqmz pmzq pmqz pzqm pzmq qpmz qpzm qmpz qmzp qzmp qzpm zmpq zmqp zpqm zqpm zpmq zpqm mzqp mzpq mqzp mqpz mpqz mpzq
pmqzonwxinecubrvalskdjfhg is when you are really bored and you have already typed every other keyboard combination out there. It happens when you type all the letters from your first and last keyboard line by turns and then typed all te letters from the middle row by turns from each end. Congratulations, you have done it!
Person one: I am really bored
Person two: Let's do your homework!
Person one: But that is also boring
Person two: Let's type pmqzonwxinecubrvalskdjfhg on the keyboard then!
The ultimate word of boredom. You typed this in because you thought you'd finally beat the internet by typing in some thing that does not exist. Well, now it does.
I was so bored, I typed pmqzonwxinecubrvtylaksjdhfg