Amazon took the tech world by surprise on Tuesday when news broke that the online mega-retailer is acquiring Ring, maker of a popular and prominent line of video doorbells. It's a big, billion-dollar move for Amazon, but after a whirlwind couple of years for the company, it still somehow feels like par for the course.

By scooping up Ring, Amazon also scoops up the doorbell's existing user base, and perhaps gives some more juice to Amazon Key, a new service that leverages smart home tech to allow for in-home package delivery. Using a smart lock to let a delivery person drop a package off inside your door is an ambitious pitch, and doing more to bring cameras into the equation might help head off potential privacy and safety concerns.

Then again, the Ring deal could also stoke some new concerns of its own. In case you're keeping track, Ring's video doorbell will be the 11th smart home product under Amazon's umbrella with either a built-in camera or microphone, joining the slew of Alexa-enabled smart speakers, the Amazon Cloud Cam and the Blink Doorbell Camera, which Amazon acquired last December. Add in the fact that Ring also sells outdoor floodlight cameras, and that brings the total up to 12 in just a little over three years. At this point, customers might rightly ask Amazon why it's so interested in these sorts of devices.

Of course, they could ask the same thing of Google, which also sells smart speakers and cameras, and which has a Nest-branded video doorbell of its own due out in the coming months. In buying Ring, Amazon throws more gasoline on its showdown with Google, only now Amazon gets a sizable head start in the number of installed smart doorbells.

The move also helps Amazon further unite its efforts to rule the smart home with its supremacy over retail. With Alexa, Ring and Amazon Key, the retailer can offer a unified smart shopping experience, from the voice order to the warehouse on through to delivery. The only thing that's missing is Amazon's own courier service... oh, wait...

In hindsight, nobody should be surprised that Amazon pulled the trigger on a purchase that will deepen its footprint in our homes. The company has made it quite clear that it's willing to spend big in order to expand the empire, and Ring seems like a pretty natural addition to the arsenal. We'll see if this acquisition leads to scores of new shoppers opening the door for Amazon's vision of the future.