Dive Brief:

• Target's summer sales event, which coincided with Amazon's Prime Day, was the highest single day of online traffic and sales of the year, the company said Wednesday.

• The most popular deals, shopped by millions of customers, were on small appliances, beauty and personal care, baby gear, and home and tech items, according to a company press release. The one-day offers came in addition to a week-long promotion for teachers to receive 15% off school supplies and back-to-school essentials, the company said.

• Nearly 90% of Tuesday's Target.com orders would be fulfilled by Target stores, part of the retailer's efforts to use stores to fulfill online orders with greater efficiency, the company also said.

Dive Insight:

Target wasn't the only retailer to chime in on Prime Day or the only one to needle the e-commerce giant by emphasizing that its sale was "for everybody — no membership required," an apparent dig at Amazon's requirement that Prime Day shoppers must have a Prime membership. Big-box retailers like Macy's, Nordstrom, Best Buy and Walmart joined Target in offering deals. Indeed, several retailers saw increased app downloads across all categories, according to data from App Annie emailed to Retail Dive. 

The timing is fortuitous for retail in that, while midsummer isn't historically a big time for shopping, consumers are thinking about back-to-school purchases, which is the industry's second most lucrative sales season. But Amazon's rivals have no choice but to counter with their own deep Prime Day discounts. A majority (63%) of consumers said they planned to shop at Amazon on Prime Day this year (half said they made a purchase there last year), and 39% said they'll look for bargains at other retailers (up from 31% who said so last year), according to AlixPartners.

There's a nice payoff, however, at least in sales. Prime Day last year increased non-Amazon brands' and retailers' sales by an average 57%, according to online ad firm Criteo. Amazon's own sales increased 60% during 2017's Prime Day and delivered $2.9 billion in sales, according to e-commerce analytics company Profitero.

But that could hit margins hard too, considering the high costs of e-commerce fulfillment, on top of the day's discounts. And that's only made worse by Amazon's extension of its sale to 36 hours.

That "ratchets up the pressure on all of retail, with 'counter measures' sure to negatively impact margins throughout the sector," Moody's Lead Retail Analyst Charlie O'Shea said in statements emailed to Retail Dive ahead of the sale. "More so than ever, we expect other retailers to roll out a heavy dose of promotions ahead, during, and after Prime Day in hopes of attracting shoppers and dollars, with some of the more challenged retailers facing the tough decision of how low to go."

Still, assuming that current high levels of consumer confidence hold, Prime Day's successful run across retail bodes well for this year's holiday sales.