The story I read said it was sales through the website alone. People will bring in old systems and games, and GS will have the employees box them up (weekly?) and ship them to their main warehouse dedicated to this. There they'll clean or address any issues, pitch the broken crap the min wage kids don't bother to check properly, then catalog, inventory, and shove it up on the website to buy.
Personally I'm all for it, as long as they don't go stuffing manuals and boxes into the incinerator. It will shove a lot more product out of hiding as people find stuff and want cash/games(modern) for their 'old crap' they don't use. Two, since they're so damned huge, they can then lowball all the scalpers online and screw with the bottom line of what sells for and still make a killing on it. And I have no problem with that either.(If they did it.)