As the web has flooded itself with flash sales and coupons, one-off deals and questionably low prices, the online market has come to resemble something of a digital Canal Street, where everything is a cheap alternative to its original self. L’ArcoBaleno, which launched earlier this year, is the extreme nonconformist, and refreshingly so—the Biennale des Antiquaires of the Internet, where fine design and rich content formally meet.