Pop-up stores are becoming an overnight sensation

For most retail stores, staying in business for only a few days would be considered a major flop.

But a growing number of merchants are opening shops and abruptly shutting them down soon after -- on purpose.

These quickie retail operations -- known as pop-ups -- are showing up throughout Southern California and around the nation, filling in the gaps at recession-battered shopping centers for a fraction of the regular rents.

Once limited to seasonal shops and dusty liquidation centers, pop-up stores are now being opened by some of the nation's biggest retailers.

It's a trend that could reshape the nation's retail landscape if it continues, diminishing the power of commercial landlords and making it easier for merchants to test new locations and products with little commitment.

"It's something that's just getting bigger and bigger every day," said Marshal Cohen, chief industry analyst at market research firm NPD Group.

Designed to generate buzz and lure shoppers with a get-in-while-you-can appeal, pop-ups allow merchants to move quickly, opening up shops to test a new product or market, and closing them without much fuss.

Gap Inc. recently opened a pop-up shop on trendy Robertson Boulevard to promote its new premium denim line; celebrities including Halle Berry and Ashlee Simpson-Wentz turned out to the shop's launch party. Toys R Us Inc. is setting up about 80 temporary toy shops nationwide, including several at upscale malls previously unavailable to the chain. J.C. Penney Co. touted its back-to-school offerings through interactive pop-up displays in half a dozen Southern California malls.

On a recent afternoon on Robertson Boulevard, Jill and Zac Stafford made an impromptu stop at Gap's pop-up shop.

The couple aren't regular customers of the casual apparel brand, but they said they were curious about the store, whose neighbors include Chanel, Rock & Republic and paparazzi haven the Ivy. Half an hour later, they left with $100 worth of new clothes.

"You feel like when you're in there that you're kind of lucky," said Zac, a 33-year-old advertising consultant.

Pop-ups' move to the mainstream was born out of the recession: Desperate landlords are able to fill vacancies in their shopping centers, and nervous retailers can get space for a few weeks or months without signing a long-term lease.