Screenshot by Donna Tam/CNET

Bummed that you're home alone on date night yet again? Don't worry. A new watch or some scuba gear could help.

At least that's the philosophy behind Singles Day, a Chinese festival that encourages those untethered by a significant other to buy themselves gifts.

Observed on November 11 -- or "11.11," for the date with the most 1s -- Singles Day has become the world's biggest online shopping day, thanks to the e-commerce prowess of China's Alibaba Group. Alibaba holds promotions and sales each year on its shopping sites on November 11. This year, Singles Day lands on Tuesday, and it's expected to generate about $8.18 billion in sales for Alibaba, up 42 percent from last year, according to market research firm IDC.

The day started out as a joke among a group of male college students attending Nanjing University in the 1990s. Originally called Bachelor Day because it was celebrated only by young men, the holiday has since morphed into a nationwide holiday for all genders, with its own traditions, according to China Daily. People eat four fried dough sticks representing the four ones in 11.11. Blind-date parties and even matchmaking fairs have become popular November 11 events.

It wasn't long before merchants realized the marketing potential of the holiday. Five years ago, Alibaba, which is China's biggest e-commerce site, began holding its own 11.11 sales. Today, Alibaba's TMall and Taobao shopping sites are filled with 11.11 promotions from thousands of business partners. The gimmick is paying off. Last year, Alibaba sold twice what all US companies sold on Black Friday and Cyber Monday combined -- those are the Friday and Monday, respectively, after Thanksgiving.

"Alibaba has picked up on it and made it its own, much like Hallmark has picked up on Valentine's Day and every other holiday," said Marlene Morris Towns, marketing professor at Georgetown University's McDonough School of Business. "It's been great for their business so far, and I think Amazon would do well to jump on it as well."

Screenshot by Donna Tam/CNET

Amazon has tried to get a piece of the action. The Seattle-based company launched promotions for the holiday last year on its Chinese site, and it's done so again this year, promoting several brands including scuba gear maker Cressi, health tech company Withings and fashion brand Vivienne Westwood. It's unclear how much revenue the day generated for Amazon.cn last year, because the company doesn't break out sales figures by region.

For Alibaba, last year's holiday translated into $5.75 billion in sales, breaking the previous year's record of $3.14 billion. It dwarfs the US's biggest online shopping day, Cyber Monday, which reached $1.46 billion in sales in 2013.

Now Alibaba has decided to take its 11.11 promotions worldwide, highlighting global brands including online jewelry store Blue Nile and clothing brand Juicy Couture. Even Costco is on board. The US-based bulk discount retailer joined Tmall in October and is promising five-day international shipping for 11.11.

"It's something that could be pretty easily promoted" in the US, said Towns. "As more people here wait to get married and get more settled into their careers and their independent lives, there's an opportunity to counter, say, Valentine's Day."