BEIJING - China's e-commerce giants are gearing up to cash in by offering online sales promotions for Singles' Day, which falls on November 11 each year.

The grassroots' self-proclaimed "holiday" developed with a self-deprecating tone among China's huge unmarried adult population, which is estimated at 180 million. It has gained popularity, proving its true holiday power by generating billions of yuan in sales for the retail business in the past few years.

A week ahead of the "holiday," online retailers' Singles' Day promotions can be seen everywhere from billboards to websites to mobile TV.

Paired with tempting words like "half-priced," "free delivery," "gifts" and "bonus," the advertisements are burning holes in some people's pockets.

"I have put the goods into my online cart and I'll pay for them on Singles' Day, as I believe the prices will be most attractive by then," said Liu Yue, a treasurer with a private company in Beijing.

She said she bought clothes, shoes and a mobile phone online on the same day last year -- all at a 50-percent discount.

Singles' Day got its name from the four "1"s that make up the date. The digits look like four bare sticks, which sounds similar to the Chinese word "guanggun," or "bachelor."

Singles' Day was first celebrated in some Chinese universities among unattached students in the 1990s. It became mainstream after Taobao, China's biggest online merchant by sales volume, launched a major promotional campaign using the concept as the theme in 2010.

On Singles' Day in 2011, T-mall, Taobao's online shopping platform, saw its trade volume skyrocket to 3.36 billion yuan ($533 million), about ten times the platform's daily average that year.

This year, 77.5 percent of B2C merchants have announced that they will roll out promotional activities on Singles' Day, according to a report released Wednesday by the China E-Business Research Center.

The commercial success of Singles' Day did not happen overnight, said Su Huiyan, a researcher with iResearch Consulting Group, a Beijing-based research firm on the Internet industry.

She said November, which falls near the end of the year, has always been a boom season for shopping. The concept of Singles' Day makes younger generations a more clear marketing target, as they have developed an online shopping habit and drive the consumption demand.

The soaring number of China's online shoppers has helped push the popularity of Singles' Day. An iResearch report published earlier this year shows that in 2011, the total number of online shoppers in China hit 187 million, representing an increase of 39 million year on year. The number also represents 36.5 percent of China's total Internet users that year.

"It's a smart marketing strategy that takes advantage of singles, as research has found that young single men and women with some savings after working for several years are more likely to spend for the feelings of joy and satisfaction," said Liu Weibing, a professor with China Youth University for Political Sciences.

This is exactly what Zhang Nan has in mind.

The 29-year-old translator with a joint venture company in Shanghai said she will console herself on Singles' Day with a shopping spree.

"It's time to reward myself with some wonderful items. I've been working so hard this year that I didn't have time to get a boyfriend," said Zhang.

However, Jin Xiaotong, vice president of the Business School of Jilin University, warned consumers make purchases sensibly and avoid impulse buying.

"Singles' Day is just another gimmick for merchants to boost their sales rather than a caring therapy to comfort those lonely souls," said Jin.