Google Will Know Which Apps You Prefer for Certain Voice Commands
You can perform a number of application functions using Google voice commands, such as playing music. While Google usually lets you choose which app to use each time, it will now know which apps you prefer and will automatically select them.
As Android Police points out, this does not refer to just one command, but rather a series of commands for a specific type. So, for example, if you say play AC / DC, Google recognizes that it is a music-related command. Later, if you say “Play Queen’s music,” Google will remember which app you prefer to use for your music bands.
An exciting new feature in Google Voice Actions that remembers which apps you want to launch for specific commands | Police Android