Re Adwords for Outdoor and Transit Advertising While not the same exact idea, I have been kicking around an idea about creating a marketplace for ad inventory

Re Adwords for Outdoor and Transit Advertising While not the same exact idea, I have been kicking around an idea about creating a marketplace for ad inventory consumers can offer. A marketplace where businesses can connect with airbnb hosts, uber drivers, college students, etc.. to place advertising in guest rooms, as bumper stickers or on t-shirts. It's not completely thought out yet. But I'd welcome discussion.