Thanksgiving holiday weekend is renowned as one of the biggest shopping events of the year, and it's set to be even larger this year than last year. If retailers are harboring any fears that in-store sales are diminishing in importance, they aren't letting them show. In fact, many retailers are opening earlier and looking to bring the benefits of online shopping into brick-and-mortar stores.

Before the big event, the National Retail Federation found an estimated 135.8 million shoppers anticipated they would go shopping either in stores or online over the four-day period. That's more than 2 million more than did so last year, and spending is expected to increase by 3.7 percent on the same basis.

Based on its tracking of Thanksgiving Day morning's online purchases, Adobe Systems Inc. has good news for retailers: The company found 24 percent more sales this year than last year, and if these trends continue, the firm is predicting $1.65 billion will be spent online this Thanksgiving, a year-over-year increase of 18 percent.

It's big money, and retailers want to make the most of it. Thursday, Macy's Inc. planned to open stores at 6 p.m. local time, Toys R Us at 5 p.m. and JC Penney Co. Inc. at 3 p.m. Some outfits, such as RadioShack, opened at 8 a.m.

Target Corp. scheduled a Thanksgiving Day opening at 6 p.m., but with a twist. The Wall Street Journal reported it called employees in at one-quarter of its stores to pack up and ship off in-store products sold online. Ahead of opening, 10 hours ahead in some cases, employees fulfilled orders for customers who took advantage of Web deals.

It's indicative of a new approach for retailers, who are seeking to capitalize on both in-store and online sales. "For those shopping from home, Target is once again making all of our Black Friday deals available on," said Tina Tyler, chief stores officer at Target.

Target isn't the only one to offer similar services. Fearful of losing consumers who don't want to brave crowds to pick up bargains, shops offer buy-now, pick-up-in-store deals. It's a useful way of appealing to customers put off by the mayhem over the weekend, while still getting them to come into the store and tempt them with impulse purchases. Research shows that 88 percent of impulse purchases are made because an item is on sale.

With some of Walmart's offers, customers are encouraged to shop in-store through special guarantees. For the fourth year, Walmart is offering a one-hour guarantee on selected in-store offers whereby customers who attempt to purchase a chosen item will be able to take it away then and there, or if it's out of stock, get it delivered.

It's one of many measures the store has taken that mean consumers are less likely to be put off by the idea of an item being out of stock. The store has highlighted the large investment it made in inventory, and offered all the same deals online as in-store to avoid the need for customers to be in the store. "Walmart will never be the retailer that broadcasts a great price on Black Friday and then ends up only having [only] a few in stock,” said Steve Bratspies, chief merchandising officer for Walmart U.S.

Regrettably, mom-and-pop stores could be put at risk by the whims of these larger retailers. Last year, mall operators in New York state threatened shops with fines for not opening on Thanksgiving, in cases where the anchor store of the mall they were in wanted to open. Stores could have been fined as much as $200 an hour for noncompliance.

Not everyone is playing the same retail game. TJ Maxx, Marshalls and HomeGoods, all owned by TJX Cos., have gone in the opposite direction. The group has even rolled out a special Thanksgiving commercial that highlights the belief Thanksgiving should be kept special, free from the pressures of sales.

If investors are worried about that approach, it didn't show on Wall Street Wednesday. The share price of  TJX Cos. Inc. was up 1.59 percent, while the share price of Wal-Mart Stores Inc. was up only 0.55 percent.