These aren't business marketplaces. These are more like classifieds, like Craigslist. Nobody wants to share their ID with a stranger, especially because how wo

These aren't business marketplaces. These are more like classifieds, like Craigslist. Nobody wants to share their ID with a stranger, especially because how would you even know if it was real? But when you click through and they're part of a genuine social network and Facebook shows you have a mutual friend, that's pretty good social proof.