Then Grubba and his girlfriend broke up. "I was stuck with all this stuff," says Grubba, 40, a corporate recruiter from Greer, S.C.

To his surprise, Sierra Trading Post took everything back, with no hassles and no questions. He lost only the shipping fees. The experience was so positive that this year Grubba turned to the Internet first when holiday shopping. He plans to buy 80% of his gifts online.

"I went out yesterday to pick up a couple of small items, and I almost went nuts driving around the shopping malls," Grubba says. "I kept saying to myself, 'Thank goodness for online shopping!' "

Grubba is part of a small but growing group of shoppers who do most of their buying online. While dot-com predictions of bustling Web sites and empty malls never came true, a few shoppers have indeed given up on stores — at least most of the time. Online aficionados are helping drive online sales to $12.2 billion, up 42% from last year, Forrester Research says.

That's forcing retailers to pay renewed attention to the Web. Sears, J.C. Penney, Circuit City and others say they're expanding services and product offerings to woo the growing groups of online shoppers. Brick-and-mortar chains with weak online offerings stand to lose customers like Grubba for good.

"Our Internet business is up more than 40% year-to-date," says Bernie Feiwus, the associate director of J.C. Penney's Internet and catalog operations. "That gets everyone's attention."

From cards to Rolex

Grubba, like many full-time online shoppers, started out small. In the late 1990s, he began collecting baseball cards of the 1950 St. Louis Browns — one of the worst teams of all time. But the cards were hard to come by in South Carolina.

So he turned to online auction site eBay, where cards were plentiful and sold for a few dollars each. Soon, Grubba had the whole team.

Grubba next tried buying airline tickets and hotel stays from Priceline.com and other travel sites. Next came hockey equipment from a store in Detroit. With each good experience, Grubba bought more online. Last year, he took his biggest plunge yet: a $3,800 Rolex bought on eBay.

At first, "You're always crossing your fingers that (online orders) come the way they're supposed to," Grubba says. "But I've never had a problem."

Why Grubba and shoppers like him are increasingly buying online:

•Experience. It has been five years since online shopping hit the mainstream. That's long enough for many people to become very comfortable with it, says retail analyst Graham Mudd at researcher ComScore. "Once people have a good experience buying that first book on the Web, they start thinking, 'What else can I buy online?' " Mudd says.

"With tenure, (online shoppers) tend to spend more per purchase and also spend more often," he adds.

Management consultant Gary Jonas, 58, started buying books and magazines online in the late 1990s. Over time, he's expanded.

Now, he'll buy almost anything over the Web. Recent purchases include 48 light bulbs and a $5,000 Segway scooter. He plans to do half of his holiday shopping online this year.

•Selection. Portland, Ore., software company owner Jeffrey Garchow plans to do 70% of his holiday shopping online — up from 10% last year — in part because he has more choices. Take the British mystery novels favored by his wife. "You go into stores and they don't have them," says Garchow. "You go online, you find a bunch."

•Convenience. It used to take Jennifer Thompson weeks to buy, wrap and ship gifts for her large out-of-town family. Now, Thompson, 32, buys more than half their gifts online.

Some limits

The stay-at-home mom shops using her Tracy, Calif., home's high-speed Internet connection. Her best shopping time: When her 1-year-old son is asleep, whether that be day or night. "I love the fact that they arrive gift-wrapped and on time, and I don't have to drag my kid — or my husband — to the store," she says.

There are some things that even experienced Web shoppers like Grubba won't buy on the Web.

Most recently, Grubba hit brick-and-mortar stores to find the perfect picture frame for a photo of a friend. "Sometimes, no matter how hard you try, you can't get that warm, fuzzy feeling from seeing things online," he says.