Amazon stresses that it won't allow notifications with advertising, and it wants developers to use notifications "sparingly." You shouldn't get an Instagram-like deluge if skill creators respect the guidelines. And there are already examples of notifications at work. AccuWeather, Domino's Pizza, family finder Life360 and Amazon's own Washington Post all have early notification support for features like news, weather and location updates.

At the same time, Amazon is taking advantage of Alexa's newfound ability to recognize individual voices. As of early 2018, third-party developers will have the option of personalizing experiences based on who's speaking. You may get different music playlists, for instance, or a game that tracks progress for specific people.

It'll be a while before these features see widespread adoption, but they both illustrate how important Alexa is to Amazon -- it's an entire platform, not just a companion service. If Amazon is going to stay ahead of Google and Apple in the smart speaker arena, it needs a voice assistant with at least some features its rivals can't yet match.