Josh Luber has two great loves: data transparency and sneakers. Four years ago, Luber was a consultant for IBM who spent his spare time bidding for rare shoes on EBay and griping that there wasn’t a good way to know how much each pair should cost. So he collected EBay’s pricing data and built the kind of guide for sneakers that Kelley Blue Book compiles for automobiles. It became the backbone of his data blog Campless. Luber’s timing was good. Thanks to sales conducted via Instagram and other social media services, the annual market for sneaker reselling has grown to somewhere between $200 million and $500 million, estimates Matt Powell, an analyst for researcher NPD. Campless got backing from billionaire mortgage lender Dan Gilbert and was transformed into StockX, an online marketplace that aims to make the prices of rare shoes as transparent as equities on a stock exchange. On other sites, Luber says, listings are just listings: “You don’t know what people are actually paying for those shoes.” Read more at Bloomberg.