What it does is rank you depending on...I don't know. Loot's a big factor, but there may be something else to it. At any rate, it skims your Armory profile, groups you up by guild, and shows your overall "rank" compared to your peers.
For example, here's my server.
My guild is ranked eighth in terms of raid progression. You can click on the guild name to see all the loot the raiders have acquired.
For another example, here's Norgannon's list.
Dagg, Dade, have your scroll wheels primed. :P
See where your group of boys and girls stand in the World of the World of Warcraft. :P