ShinyLoot has been pretty "dormant" for a while now.
I must say, I don't really get how Steam-key resellers make money. Places like GOG and HumbleBundle that sell DRM-Free "copies" are different, but places like GreenManGaming, GamersGate and various "bundlers" are just selling something they must have "bought" from Steam, same as I can do. I bought "Cities:Skylines" from GMG for a discount. It's available from the publisher (Paradox) or Amazon, but both are just Steam keys.
The one game I bought at ShinyLoot came with both a Steam key and a zip download.
EDIT
I've been reading more about how this economy works. Apparently as a developer, you just ask Steam for keys and they give them to you. The store (GMG, HumbleBundle, or whatever) then buys the keys from the developer and resells them. Steam makes money by (1) selling games itself and (2) providing DRM to developers. So GMG et al are not "resellers" of steam keys since they're likely getting them directly from the developer or publisher.