You can now break down unwanted and otherwise worthless marketplace items into gems, which can be used to buy card boosters or bid on games.
The gem crafting system is broken somehow, and people have managed to get billions of gems.
A lot of people speculated on gems, and have lost money, because they are now effectively worthless, since there are billions of extra ones out there.
Valve can't get rid of the gems, because they are marketable, and legitimate customers have spent money on them by now.
The better question is what happens to those that exploited the bug to get gems that they then sold on the market?