At the new Rebecca Minkoff store in San Francisco, the mirrors come alive. Walk into the fitting room with, say, a blouse and a jacket, and the dark glass lights up with a suggested handbag to match. You can browse the racks at the upscale fashion boutique or swipe through "looks" on massive touchscreens. If you see something you like, you tap in your phone number, and you'll get a text when it's ready to try on.

From the sharp interface design to the seemingly seamless fusion of digital connectedness to physical retail, this place feels like the brick-and-mortar store of the future. But the brains behind it come from the online world. This Rebecca Minkoff store and a partner location in New York are opening for the holidays to show off eBay's latest tech for re-inventing in-store shopping.

Yes, that eBay.

Though most consumers still think of eBay strictly as an online shopping destination, the company's official corporate mission is to strive toward becoming a venue for all commerce. And that means integrating itself with the physical world, where the vast majority of retail still takes place.

Echoing the efforts by so many other internet companies to invade the physical world—from Amazon to Foursquare—the eBay mirrors flip the standard script in which offline stores struggling to catch up by porting their physical presence online. In this case, both eBay and Rebecca Minkoff—which started as an online-only brand—are venturing offline in a recognition that the future of shopping will include elements of both.

"People still want to use their five senses, not just the one sense you use when you're doing e-commerce," says Steve Yankovich, eBay's head of innovation and new ventures. "So physical retail, a showroom, I think will never go away."

From Novelty to Expectation

The "connected" Rebecca Minkoff stores include a feature becoming more common in physical retail, in which the store will "recognize" users of its mobile app, allowing staff to see who's in the store and what they've bought. Using that purchase history, the staff can act like a human version of Amazon's recommendation engine.

The stores are also equipped with cameras that are able to track individual shoppers (anonymously, eBay says) through the store. By observing shopper behavior, store managagers can tweak everything from layout and display to price, mimicking the kind of A/B testing and analytics commonplace on e-commerce websites.

The digital mirror-equipped stores are opening just as eBay appears to be rethinking another experiment in offline retail. The company has pulled its eBay Now same-day delivery app from the App Store, apparently in favor of integrating the service into its main app. In keeping with eBay's basic idea of serving as a platform to connect buyers and sellers, eBay Now worked by letting shoppers place orders that drivers filled by buying the items direct at local chain stores.

One possible appeal of eBay Now to brick-and-mortar stores like Staples and Walgreens was that it gave them a way to compete with Amazon's move into same-day delivery. But it's unclear how much demand for such a costly service exists. The magic mirrors, on the other hand, integrate aspects of online shopping with the most traditional form of retail gratification: actually being there. Whether eBay ends up becoming a major provider of physical retail tech remains to be seen. But as mobile devices make computing a ubiquitous presence in the physical world, the kind of digitally augmented experiences eBay's experiment with Rebecca Minkoff envisions will no longer be a novelty—it will be expected.