Online vintage company ThredUp's announcement that it will open small shops inside both Macy's and JC Penney is a game-changer. Will mainstream American shoppers bite, or balk?

Q&A with Patrick Robinson, a general partner at investment firm CircleUp, who's not enthused about the pure D2C model.

Despite all the hoopla over D2C brands, retail sales of clothing fell 24%, the worst month since the recession of 2008.

It just announced Personal Shopper by Prime Wardrobe -- which, like Stitch Fix, sends subscribers a curated box of clothing choices every month.