The weather, Amazon and the sluggish economy were all cited as reasons for this season’s weak retail earnings. However, another, less-talked about threat is hovering over the beleaguered sector: so-called resale sites. This subset of e-commerce, which is aimed at consumers who interact socially to buy and sell items online, is on the rise thanks to fashion apps like Poshmark, thredUp and Tradesy. While the notion of consumers selling items online is not a new phenomenon, experts say this method of shopping is more focused, because users seek out a particular style rather than search for a specific item. “It’s almost like you can follow a stylist, peek into their closet and get items cheaper. It’s like having a personal shopper,” says Stacey Widlitz, president of SW Retail Advisors. See more at CNBC.