The strip lights in the hypermarket know where you are, and can tell you where to go. The new technology being trailed by French retailer Carrefour tracks your movements and beams data to your smartphone via light pulses undetectable to the eye, to guide you to the right shelves for tailored special offers.

If eBay and Etsy were as easy as Instagram, would you sell more stuff? Old iPhones, unloved sweaters, and those Civil War sock puppets you?ve been working on? A crowd of entrepreneurs and their investors are betting heavily that you would, building mobile platforms intended to strip some of the friction out of peer-to-peer commerce.

Comcast Corp. and Time Warner Inc. are investing in virtual reality, the latest traditional media players to bet on the emerging technology amid big disruptions in pay television.

Airbnb is dialing back its attitude and says it will play nicely with cities looking to regulate its business.