From the quote on the front page, it is obviously going to be the scaling of players option if they enter old content, not in the form of LFR i think, just exactly the way Challenge modes work now.
You would make a raid group, go to ICC or Sunwell or something, RL turns it to "Scaled" and bam, old content with transmog, valour, gold, mounts/pets as rewards.
The reason I say it wont be LFR style is because the number of people running it will most likely make queue times insane, where as with challenge modes if a group is bored they can go do some old raids which don't die in seconds for the above rewards.