In the new world of retail, every day between Thanksgiving and Christmas is Black Friday and Cyber Monday.

People still lined up outside Target and Best Buy in the wee hours of the morning searching for deals, but high-speed Internet connections and increasingly sophisticated mobile devices have turned holiday shopping into a 24/7 experience. "We see more and more different ways to entice customers," said Dave Brennan, professor of marketing and co-director of the Institute for Retailing Excellence at the University of St. Thomas.

Black Friday and Cyber Monday represent an era when stores were stores and the Internet was the Internet. Shoppers went to stores on the Friday after Thanksgiving and then shopped online the following Monday. But the difference between a physical store and online experience has become less and less clear, Brennan said.

For example, Best Buy, based in Richfield, already offered some of its best online customers an early crack at Black Friday merchandise. The new Herberger's department store at Southdale Center contains kiosks that allows shoppers to order products off its website. And in an ironic, retro twist,, which pioneered online shopping, recently purchased paper circulars in Sunday newspapers.

"No need to wait, our Black Friday deals start November 21," the circular said.

Holiday online sales have been booming in recent years, often at the expense of their brick-and-mortar cousins. For the first 20 days of the November to December holiday season, Internet sales have soared 16 percent to $9.67 billion from $8.47 billion during the same period a year ago, according to ComScore, a data analytics firm.

For the entire holiday season, ComScore estimates online sales will total $37.6 billion, a 15 percent gain over 2010.

Soaring online holiday sales "reflect the significant channel shift we're witnessing from offline retail," ComScore Chairman Gian Fulgoni said.

What's helping to drive the increase is the proliferation of mobile devices like smartphones and tablets, which consumers are using to research products, compare prices, redeem coupons, and yes, buy stuff.

In a recent survey conducted by the National Retail Federation (NRF), 52.6 percent of shoppers say they will use smartphones for holiday shopping. Of that group, nearly 35 percent said they will purchase merchandise through their smartphones.

Tablets fared even better. In the NRF survey, 70 percent of respondents said they would incorporate tablets into holiday shopping with nearly a third planning to purchase something through the device.

As a result, retailers like Target Corp., based in Minneapolis, and Best Buy are building fewer big-box stores and embracing "multichannel shopping." The concept means retailers consistently engage consumers over a variety of platforms, including stores, call centers, websites, mobile devices.

But that's easier said than done. Target and Best Buy still generate the vast majority of sales from stores. And has had a rough start since its relaunch in August, crashing twice and frustrating customers with shipment delays and payment snafus.

That's why Black Friday still matters to retailers, especially to companies like Target that are still struggling to integrate their store and web operations, said Devon Wolfe, managing director of strategy and analytics services for Pitney Bowes Business Insight. For the most part, the two sides don't work well with each other, often to the frustration of the company, he said.

Part of the reason is how retailers credit the competing channels. For example, a customer purchases an item online but picks it up at the store. The company counts that as web sale even though store employees provide all of the service, Wolfe said.

"Stores get no credit," Wolfe said.

However, retailers are getting better at solving such problems. And once they master multichannel shopping, the relevance of Black Friday and Cyber Monday will fade.

While many older shoppers still favor the familiar Black Friday experience, they will inevitably give way to younger consumers more comfortable with mobile technology.

According to the NRF survey, 70 percent of Americans aged 18 to 24 say they will use their smartphones for holiday shopping, and 86.4 percent plan to buy on their tablets.

As those shoppers enter the mainstream, Brennan said, Black Friday and Cyber Monday will become just another day of the week.

Thomas Lee • 612-673-4113