https://phys.org/news/2018-07-amazon-prime-day-foods.html

"They want Prime to be a must-have membership," says Suzanne Tager, who heads Bain & Co.'s retail and consumer products practices.

Prime Day, created by Amazon in 2015 to mark its 20th anniversary, has inspired other e-commerce companies to invent their own shopping holidays. Online furniture seller Wayfair introduced Way Day in April, becoming its biggest revenue day ever. While Prime Day brings in more revenue for Amazon, too, it also helps boost its Prime memberships. It had more sign-ups during 2017's event than any other day in the company's history, Amazon said at the time, without providing specific numbers.