Designers, celebrities and shoppers in cities from New York to Milan roamed boutiques and stores in droves on Thursday as part of the fourth annual "Fashion's Night Out," a global event to encourage spending.

The event, held on the first night of the semi-annual Mercedes-Benz Fashion Week in New York, is the brainchild of Vogue magazine editor Anna Wintour and was designed to jump-start an industry battered by the global recession in 2009.

"Fashion's Night Out," has since turned into a global night of retail revelry in 19 countries, according to organizers, as store stay open late and offer drinks, entertainment and free products to the throngs.

"We come out to see everybody and what they're wearing. Every year (the stores) are trying to do something bigger and better and it's cool to see.... It's the buzz of the city," said Brittany Wolf, 24, who helps branding for an accessories line, Theodora & Callum, in New York.

In New York, the night was expected to attract tens of thousands to the approximately 900 stores, said George Fertitta, head of NYC & Company, the city's official marketing and tourism organization.

In Paris, thousands converged on the city's the 8th district, blocking traffic for several hours on two boutique-studded avenues. The center of Milan was also packed with potential shoppers, many of them students, sipping from plastic glasses of free cocktails dispensed by nearby boutiques.

In London, about 400 stores were participating, according to a spokesperson with Conde Nast, the giant high-end magazine publisher that owns Vogue. Sydney's night out had over 600 retailers participating, with some offering products only on sale that night, Vogue Australia said on its website.

The extra publicity the night can bring to stores and designer brands is as important as getting customers out to the stores, Fertitta said.

Bloomingdale's flagship department store in New York, featured members of the band Matchbox Twenty, hip-hop artist and designer Pharrell Williams, and actor Kellan Lutz from the "Twilight Saga" films.

At Colette, a clothing and accessories boutique in Paris, celebrity stylist David Mallet applied hair extensions for shoppers while at Chloe, nearby, customers watched a cheerleader show with editor-in-chief of Vogue's French edition, Emmanuelle Alt.

"(The stores) compete with each other ... in terms of who's going to be the most exciting, who's going to the most fun, who's going out be the most interesting," Fertitta said.

"GETS PEOPLE IN THE DOOR"

Organizers and designers say the event has been effective.

"We always have good selling and (FNO) gets people in the door," said designer Rebecca Minkoff, best known for her line of handbags. She was part of New York luxury store Saks Fifth Avenue events for the night.

Data from NYC & Company found that two thirds of stores who participated in 2011 and responded to their survey said store traffic increased as a result of the night.

"What happens is there's a big bump in the stores the following week or 10 days after that," Fertitta said. "People go and they see ... and then they go back to the stores and buy what they want the next day."

Given that retail sales have picked up over the summer, buoyed by an improving economy, stores could see an extra benefit this year.

High-end retailers have fared well. Nordstrom Inc's same-store sales, a key industry gauge that tracks sales at stores open at least a year, rose more than 20 percent last month while Saks Inc and Neiman Marcus Group similarly reported strong quarterly results.

In August, top U.S. retail chains such as Macy's Inc and T.J. Maxx owner TJX Cos Inc saw same-store sales rise 3.6. percent.

'LONG LINES, ALL THE SAME PARTY'

Critics say that with the lines to get into stores and the full-price of items, the shopping event is underwhelming.

"The lines are long and it's all the same party," said Ross Cameron, who was taking a subway to his home, just blocks from a main strip of New York designer stores holding events.

Others like Deneene Wyatt, 26, of New York who planned to visit all her favorite stores after visiting Diane Von Furstenberg in downtown Manhattan, said she was there for the fashion not the prices.

"If you like it, you're going to buy it anyway," she said.

(Additional reporting by Elizabeth Pineau in Paris, Antonella Ciancio in Milan, and Phil Wahba in New York; Editing by Jackie Frank)