For those not in the know, an "LP" is a "Let's Play", similar to an After Action Report but the author posts as he plays the game instead of after it's done.
They are often done with some audience-participation.
I know that the last winner of the massive megagame, Zeldor, is in the process of turning his victory into an After Action Report.
Here's a link to the thread mentioned in the OP where the player Matryx is EA R'lyeh in a newbie game.
As far as I know, Matryx still actively hosts games over at Something Awful?