Which begs the question - How they hell are they getting so many coal pieces? trading? multiple accounts (I have had my kids give me a few they earned through the F2P games)?
As Dan said, they abused the Humble Bundle. (What? People abusing something that was mean for good? Noooo.) Every Steam account gets about 5 free gifts just by having a single activated game. They give you 2 free at the start, then you get one by recommend a game, posting on someone elses' account, etc.
What are they actually accomplishing from this? Honestly, very little. I would say it would take no less than 3-5 minutes to set up a Steam account with the Humble Bundle to get those 5 gifts, which are most likely 3 coal and 2 coupons, with a rare game here and there.
Do that a hundred times in 3 hours, and you got some chances at the Steam giveaway, some games you probably find worthless (or are on sale for $3-4 anyway), and coupons.