Amazon's third installment of Prime Day is in the books and has officially been crowned the biggest single-day sales haul in its history.
The ecommerce giant said the Prime Day 2017 event grew by more than 60 percent compared to the same 30 hours last year, which was itself another record-breaking sales day for the company.
In terms of Amazon-branded devices, Amazon said Prime Day shoppers bought more than seven times as many Alexa-powered devices as compared to Prime Day 2016, with the event bringing in record sales for the Echo, Fire tablets and Kindle. Prime members' most popular purchase on Prime Day was the Echo Dot, Amazon said.
Impressive as the sales tally may be, to Amazon, sales are only a secondary goal during that one-day event. Prime Day is a benefit exclusive to Prime members, which means non-Prime customers had to subscribe to the service -- albeit with an optional 30-day free trial -- to access the deals.
Amazon does not provide exact details on Prime signups, but it did say that more new members joined Prime on July 11 than on any other day in the site's history.
"Tens of millions of Prime members made a purchase on Prime Day 2017, more than 50 percent higher than the prior year," Amazon touted in a press release release.
Additionally, research from Consumer Intelligence Research Partners (CIRP), a firm that's been tracking Amazon Prime's growth for the past couple of years, has found that those who sign up for the free trial end up converting into paying members roughly 73 percent of the time. And after one year, 91 percent of members renew for a second.
With that setup, Prime Day becomes more of a customer retention and acquisition play for world's largest retailer. Why? Because the continued growth of Prime membership is crucial for its future dominance. Prime members spend an estimated $1,200 a year on Amazon, non-members spend roughly $500, according to CIRP.
Amazon devices also factor in to the Prime Day equation. Amazon is betting long term on voice enabled commerce, and all of those newly sold Alexa-powered devices provide yet another opportunity for Amazon to enter the home and offer customers more ways to shop within its digital ecosystem.
"To those customers who tried Prime for the first time and our long time members, thank you for a great Prime Day," Greg Greeley, vice president of Amazon Prime, said in a statement.
"Our teams around the world will keep working to add more and more to your membership, so Prime continues to make your life better every day. We are already looking forward to our Prime Day celebration next year."
See: Shipping to data: The case of Amazon Prime Day | Prime Day: A showcase for Amazon's engagement 'echosystem' | Amazon rolls out Geek Squad-style home services | Amazon's Prime Day marks debut of Prime Air cargo planes, a FedEx, UPS threat | Here's why Prime Day is more than a sale | How to make the most of Amazon Prime Day | Amazon Prime Day, Echo deals meet peak disruption storyline