(Reuters) - Retailers are targeting "post-pie" commerce, the jump in shopping created by the boom in smartphones and tablet computers which Thanksgiving diners grab as they collapse onto the couch after eating turkey and pumpkin pie.
While people relax with family and friends or watch football on TV, they are increasingly shopping online with these mobile gadgets, creating a surge in traffic and purchases that retailers are beginning to target for the first time this year.
"This is a new shoppable moment," said Steve Yankovich, who heads the mobile business of eBay Inc, operator of the largest online marketplace.
Before the rise of smartphones and tablets, it was socially unacceptable to pull out a laptop after Thanksgiving dinner, or head to a home office to fire up a desktop computer, Yankovich explained.
"With a tablet or smartphone you don't get that reaction," he added.
EBay recently surveyed more than 1,000 shoppers in the United States about their holiday shopping plans. Almost two thirds said holiday sales should begin after Thanksgiving dinner and respondents said their meals would end, on average, at 5:23 p.m. EST.
Based on that feedback, eBay plans to launch 20 mobile-only deals through its eBay Mobile application at 5:23 p.m. EST this Thanksgiving. The company plans 20 more at 5:23 p.m. PST for West Coast shoppers.
Other retailers including Toys "R" Us, HSN Inc, Rue La La and ideeli are also targeting mobile shoppers this Thanksgiving in the evening.
"The iPad holiday sales season starts at the point of indigestion while you're sitting on the couch after Thanksgiving dinner," said Ben Fischman, chief executive of Rue La La, which specializes in online limited-time fashion sales events known as flash sales.
Post-pie commerce is the latest example of how mobile devices, in particular Apple Inc's iPad and iPhone, are changing consumer behavior and forcing retailers to adapt quickly.
The holiday shopping season traditionally kicks off with Black Friday, the day after Thanksgiving when shoppers use a day off from work to head to stores.
The following Monday became a big online shopping day known as Cyber Monday because people returned to the office and shopped using their office computers.
Now Thanksgiving is emerging as a big new shopping day online. The value of e-commerce transactions on Turkey Day has surged 128 percent to $479 million over the past five years, outpacing the growth of Black Friday, Cyber Monday and other big holiday shopping days, according to comScore Inc.
That's a far cry from the $1.25 billion spent online on Cyber Monday last year, but the growth has caught retailers' attention.
"It's still a smaller day, but it is growing much faster," said Andrew Lipsman of comScore. "We're seeing a lot more talk about Thanksgiving becoming a more important shopping day."
Several big retailers, including Target Corp, are opening physical stores on Thanksgiving to make sure they don't lose sales to online rivals.
"Consumers that would rather shop than watch 12 hours of football on Thanksgiving Day should be given the chance to shop," Marshal Cohen of The NPD Group wrote in a blog on Thursday. "If online is open, why should brick-and-mortar close just to give away those precious shopping hours to the competition?"
Thanksgiving evening is where the action is online. By 3 p.m. EST last year online sales were up about 20 percent compared to the same period in 2010, according to IBM Software Group, a unit of International Business Machines Corp.
But by midnight PST on Thanksgiving 2011, online sales were up 39 percent versus the same period the previous year, IBM data show. Overall, November 2011 online sales rose 15.6 percent compared to the year-earlier period.
"Post-pie shopping this year will be fueled mostly by tablet shoppers, especially iPad users," said Jay Henderson, global strategy director for IBM's enterprise marketing management business.
In September and October, the iPad accounted for at least 7.5 percent of all traffic to retailers' websites, beating out the iPhone with about 6 percent and Android devices at just over 4 percent, IBM data show.
"This is the first time the iPad has shown sustained leadership over all other mobile devices," Henderson said.
Last Thanksgiving, retailers were surprised by the surge in tablet traffic in the evening. They also did not expect the devices would be used to complete so many purchases, instead expecting them to be browsing devices mostly, according to Steve Tack, chief technology officer for APM Solutions, a unit of Compuware Corp.
"Tablet users are not waiting for Black Friday or Cyber Monday to purchase, they are doing it on Thursday night on the couch in front of the game," he said. "This is a significant new shopping event."
This year, retailers are more prepared, he added.
Rue La La will launch an online boutique called "The Holiday Dash" at 8 p.m. EST on Thanksgiving, "specifically to go after the shopper who will be sitting at home after dinner on the couch," CEO Fischman said.
More than half of Rue La La's sales over Thanksgiving, Black Friday and the following weekend will come from mobile devices. Half of those mobile purchases will be on an iPad, he said.
Fischman said the conversion rate on an iPad is close to double the conversion rate on a smart phone, meaning shoppers are more than twice as likely to purchase using the tablet device.
"The tablet offers the luxury of a larger screen with the convenience and portability of the phone," Fischman said. "It's the killer e-commerce device."
Ideeli, a rival to Rue La La, plans a "Think Fast" online sales event at 6 p.m. EST on Thanksgiving to target tablet shoppers. Ideeli usually runs sales at noon every day.
Toys "R" Us, the largest toy retailer, launched a new tablet-optimized website on Tuesday and the company plans to make all its Black Friday deals available online at 8 p.m. EST on Thanksgiving.
HSN, which runs the Home Shopping Network and has traditionally focused on TV sales, on Tuesday unveiled an online holiday gift guide designed for tablet shoppers.
The company plans to send discounted deals to mobile shoppers on Thanksgiving.
"When people are done with the holiday meal and go back into the screen world, we will have great products on sale," said Jill Braff, executive vice president of Digital Commerce at HSN.
Reporting by Alistair Barr in San Francisco; additional reporting by Lisa Baertlein in Los Angeles; Editing by Phil Berlowitz