Why do China's biggest brands celebrate being single every year?
Millions of people in China are celebrating being single on the social network Sina Weibo - because it's "Singles Day" on 11 November. Here's BBC Trending's quick guide to the day and the huge viral phenomenon, driven by online retailers, that it has become.
What is it?
It's meant to be a day set aside for single people to spoil themselves. The date is four single 1s - 11.11 - or as they call it in China, "bare sticks" - in other words, you're unattached.
Who started it?
It's hard to be sure but an often repeated explanation is that it started as a grassroots movement among students at Nanjing University in the early nineties. They bought themselves presents, as a sort of "anti-Valentines day".
So it's just grown from there?
No - it's grown because of heavy promotion by online retailers and brands. In 2009, the online retail giant Alibaba decided to turn the day into a massive marketing opportunity. Every Singles Day, Alibaba offers huge discounts, aimed at those who are single. It's also a shopping day for other brands and retailers - China Daily called it "China's Black Friday" last year, comparing it to the big US sales day after Thanksgiving, after sales of 10 billion yuan (US $1.63 billion) were recorded on just one online shopping site.
So it's big, then?
It's one of the biggest online conversations each year. It's perhaps no surprise that the Singles Day hashtag on Weibo has reached hundreds of millions of people over the years - because the online retailers who help drive it know their sites are just a click away.
But wait - people are also getting married this "Singles Day"? Er...
This appears to be a growing trend. Last year, the Xinhua news agency reported a "wedding boom" on Singles Day. It seems some people see the "bare sticks" next to each other (11.11) as a romantic symbol of singles finding one another.
What's this picture?
This twist on Communist-style propaganda art is used all over the internet to represent Singles Day, including on the Weibo page for the hashtag. The slogan translates as: "Our Singles Day strength".
What's going viral this Singles Day?
The Chinese account of the US sitcom, the Big Bang Theory, has been making jokes about the upcoming day on Weibo. Some students are sharing selfies of themselves holding boards explaining why it's OK to be single and stating that they aren't interested in finding a partner. One student has dreamt up a fake "Singles card" that looks like a marriage licence, which is also drawing clicks. But big brands are still among the top Singles Day trends.
Research by Kerry Allen
Next story: Should drivers over 70 years old be retested?
A man whose wife killed by an elderly driver, who mistook the accelerator for the brake, has started a popular online petition calling for over-70s to be retested every three years.READ MORE