Amazon’s third annual Prime Day has come and gone. This year’s event now ranks as the biggest sales day ever in Amazon history, surpassing both Black Friday and Cyber Monday, according to an Amazon statement emailed to Retail Dive.

Prime Day 2017 — which lasted 30 hours this year compared to 24 hours for the two previous events — grew by more than 60% compared to the same 30 hours last year, and sales growth by small businesses and entrepreneurs was even higher, Amazon said.

The Echo Dot was a big winner this year. The portable Alexa-enabled speaker was not only the best-selling Amazon device, but also the best-selling product from any manufacturer in any category across Amazon globally, according to the company. Prime members purchased seven times more Amazon Echo devices globally during this year’s event than on Prime Day 2016.

But Amazon really hit the mother lode in growing its Prime membership program as more shoppers joined to access deals. More new members joined Prime on July 11 than on any previous day in Amazon history. “Tens of millions of Prime members made a purchase on Prime Day 2017, more than 50% higher than the prior year,” the company said in a statement.

“Amazon is defying the traditional laws of retail physics which dictate that growth slows after a retailer reaches 25% market share. This demonstrates how different Amazon is from any other retail entity,” Matt Sargent, senior vice president of retail at Frank N. Magid Associates, told Retail Dive in an email. “The ability of Prime to build aggressively upon its base (42% of US consumers) demonstrates that Amazon is succeeding in its strategy to build an ecosystem that is undeniably attractive to all customers.”

The day before Prime Day, Retail Dive listed nine reasons why Prime Day matters — to Amazon and the rest of retail. Today, we break down the five biggest takeaways from this increasingly significant event in retail.

1. Prime Day 2017 had fewer fails

There were similar criticisms as in years past — #PrimeDayFail made its return on social media — but overall, the event ran rather smoothly. Amazon, it seems, is learning from its mistakes.

“Between the cross-channel marketing activity leading up to Prime Day, and the structure and categorization of the deals themselves on Prime Day, it is clear Amazon strategized to make the shopping experience easier for consumers to navigate this year,” Ryne Misso, director of marketing for Market Track, told Retail Dive in an email. “This is likely a reaction to much of the consumer feedback seen across social media channels after the first two Prime Days, which criticized the event for not offering deals on popular categories and products.”

2. Targeted deals grew key categories, but grocery lagged

On Prime Day, Amazon was strategic in its selection of products and categories to feature, and grouped them by “most-shopped themes,” such as items for pet lovers, gardeners and kids. The most popular themes on Prime Day were those for home Chefs, techies and “for the home.”

Electronics, toys and even apparel were called out in Amazon’s press release Wednesday morning. Amazon tends to create bulleted lists of specific best-selling items to illustrate the vast volume of goods moved in any given event.

On Prime Day 2017, “more than 3.5 million toys were purchased” and “more than 200,000 women’s dresses and more than 200,000 lightbulbs were purchased by customers,” among many others. But while Amazon strategically offered deals in the grocery category, the early results fail to mention much in the way of popular items purchased on Prime Day.

Not much was said about grocery — and that’s worth noting. Grocery is a key category that Amazon is looking to grow, with the company’s $13.7 billion acquisition of Whole Foods Market and other weapons — including proprietary technology — at its disposal.

“Nearly 70% of the Alexa-only Prime Day Deals were for CPG products, from candy to home consumables such as…