NEW YORK >> Shoppers buying on their phones this holiday season will see new ways stores are making it easier and faster as they try to lock in sales before people swipe to the next site.

“It’s not just a shopper’s tool,” said Tamara Gaffney, principal analyst and director at Adobe Digital Insights, the research arm of Adobe Systems. “It’s now so embedded in our existence we don’t even think about the fact that we pulled out our phone and bought things.”

Mobile shopping accounted for $4.61 billion in sales from Thanksgiving through Monday, according to Adobe Digital Insights. Some 54 percent of visits to retailers’ sites and 36 percent of sales for the five-day period came from phones and tablets.

Here are four ways smartphones are changing the way people shop — and how retailers are responding:

MORE IMPULSE BUYING: Mobile shopping entices people to buy right when they’re thinking about it, Gaffney said, “It’s this sense of urgency.” She noted that retailers that had more mobile traffic enjoyed a 30 percent increase in online revenue.

Retailers need to make it easier to find items so shoppers don’t quickly move on.

“They want it fast,” said Peter Cobb, co-founder and executive vice president of eBags, which says mobile accounted for 43 percent of visits and 20 percent of sales for the five-day period. The handbags and luggage site now highlights the top five sales hits to save people from sorting through 90,000 products.

Wal-Mart Stores Inc., which has worked to improve its app including the browse feature, said 70 percent of Walmart.com traffic and 60 percent of orders Thursday and Friday were driven by mobile devices.

FOCUSED ON DEALS: Even in an improving economy, shoppers are fixated on deals — and mobile phones make it easier to grab them.

Customers look to have spent nearly 3.5 percent less on average for the four-day weekend starting Thursday than a year ago, according to a survey conducted over the weekend by the National Retail Federation trade group. Much of the drop had to do with the heavy discounting shoppers demand. The NRF’s survey showed more than 36 percent of shoppers said everything they bought this past weekend was on sale, compared with 32.5 percent a year ago.

Retailers are shifting to a stream of discounts and alerts during the entire week via email and social media. Toys R Us is doing more flash sales, and eBags introduced a page called “Steals and Deals” highlighting items that are heavily discounted for a limited time.

Market Track, which monitored nearly 1,500 products online from Thanksgiving through Cyber Monday, says stores changed prices more often than last year, and more were lowered than raised.

Some 41 percent of prices shifted at least once, compared with 27 percent last year, said Traci Gregorski, senior vice president of marketing. About 16 percent changed more than once, compared with only 7 percent in 2015.

SEEKING SPEEDIER SERVICE: People buying on the go want a swifter response when they need help.

“When you have shoppers who are engaged, you have to try to capture as much revenue as you can,” said Kevon Hills, senior vice president of operations at StellaService, which tracks customer service for retailers and online companies.

Two years ago, 97 percent of retailers offered email as a way to interact with customers, but that fell to 81 percent heading into this holiday season, StellaService said. Some 90 percent use live chat, up from 80 percent two years ago. And in 61 percent of chat interactions over the holiday weekend, someone responded within 20 seconds, up from 45 percent a year ago.

Cobb says eBags has started using Facebook messenger to interact with shoppers.

VISITING STORES FOR DIFFERENT REASONS: Even people who’d bought lots of items on their phones were spending time in stores on Saturday and Sunday, said Marshal Cohen, chief industry analyst at research firm NPD Group Inc.

“In the past, consumers did their research online and then purchased in-store, but brick and mortar stores are now critical to consumers’ research needs,” he wrote in a blog post. He said “consumers came and bought, impulsively and socially.”

Technology beyond shopping apps means people use stores differently.

“They do research online, compare prices, look for deals and even try on an outfit and Snapchat it to a friend, all while in the store,” said Tom McGee, CEO of the mall group International Council of Shopping Centers.

They’re also using the phone to buy right in the store.

Many retailers believe letting online shoppers pick up their orders at stores is helping bring mobile shoppers back. Wal-Mart says nearly half of its pick-up orders came from mobile purchases over the five-day weekend, and that shoppers buy more items when they come to collect their goods.