What Would Alexa Do?

Every once in a while, a product comes along that changes everyone's expectations of what's possible in user interfaces. Alexa belongs in that elite group of game changers. Siri didn't make it over the hump, despite the buzz it created. Neither did Google Now or Cortana, despite their amazing capabilities and their progress in adoption. But Alexa has done so many things right that everyone else has missed that it is, to my mind, the first winning product of the conversational era.