CES 2017: Amazon's virtual aide Alexa shouts above rivals

Virtual assistants are everywhere at CES this year - but one speaks louder than the rest. Amazon's Alexa has popped up in a bewildering list of devices including fridges, cars and robots. Manufacturers are clearly interested in making their appliances voice-operable, and many see Alexa as a great way to do this. But having Alexa also allows the appliances to gain capabilities, such as streaming music and turning smart lights on and off. How did Alexa come out on top and how will it benefit Amazon?