Call me a Syscoin advocate, but wasn't Syscoin's Blockmarket the world's first decentralized marketplace?
Or is Bitbay currently open for public use?
Don't forget Nxt Marketplace (aka Digital Goods Store) in the Nxt core and the Freemarket add-on.
http://wiki.nxtcrypto.org/wiki/Marketplacehttp://nxtfreemarket.com/Each of these projects (BitBay, Syscoin, Nxt, and other blockchain based market places) should know about each other. Competition is good and hopefully will result in a better over-all user experience in the long run.