Amazon.com has recently confirmed it shipped over a billion items this holiday season. Recent estimates are predicting that the online retail juggernaut post its 2016 revenue of roughly $137 billion, good for year-over-year growth of 28%.

Perhaps unsurprisingly, Amazon just confirmed its best-selling product in 2016 was one of its own making: its none other than the new Alexa-enabled Echo Dot.

Alexa-enabled Echo Dot

According to Electronic House, "Echo Dot is the best-selling, most gifted item on Amazon.com with millions sold worldwide since launch."

"Echo and Echo Dot were the best-selling products across Amazon this year," elaborated Amazon Worldwide Consumer CEO Jeff Wilke, "and we're thrilled that millions of new customers will be introduced to Alexa as a result. Despite our best efforts and ramped-up production, we still had trouble keeping them in stock."

One of the most attractive details about Echo Dot was its affordable price point of $49.99, and helped steer Amazon towards its estimated 2016 revenue of roughly $137 billion. Which amounts to impressive year-over-year growth of 28%, Business Insider has learned.

Alexa is Amazon's virtual personal assistant, or as Amazon puts it, "the brain behind Echo Dot."

With the help of far-field voice-recognition technology and an array of seven microphones in Echo Dot, a delightfully small, hands-free device that can be placed anywhere in your home, consumers can perform a staggering array of tasks using only voice commands, such as playing music, ordering a pizza, requesting virtually any information, calling a ride from Uber, controlling compatible smart-home devices, and of course, ordering items from Amazon.com.

Amazon's Alexa-enabled Echo Dot is a hands-free, voice-controlled device that uses Alexa to play music, control smart home devices, provide information, read the news, set alarms, and more

Amazon.com (often simply Amazon) is an American electronic commerce and cloud computing company, founded on July 5, 1994, by Jeff Bezos and based in Seattle, Washington.