Google just revealed that half a billion people around the world are using the Google Assistant as it battles with Amazon to conquer the smart home (GOOG, GOOGL)

· Google just announced that 500 million people around the world are using the Google Assistant, its voice-activated digital assistant.
· The milestone was announced just ahead of CES, the annual tech conference in Las Vegas where Amazon's Alexa has had a growing presence in recent years.
· Google hasn't previously said how...