But having initially been a day for young singles to meet future partners, and also eat lots of deep fried dough sticks and dumplings, it's also a day of pure commercialisation, and Alibaba is hoping to cash in – big.
Last year the etail giant took around £3.6bn in sales – this year Jack Ma's firm, which includes T-Mall, a site many UK retailers sit on, and TaoBao Marketplace - is expecting to grow that to a whopping £5.2bn. That's just in one day.
Alibaba reportedly took $1bn in its first 20 minutes – this time last year it took an hour to reach that milestone. By one hour and 12 seconds it had notched up $2bn in sales and it had reached $5.9bn by 1:30pm local time.
For context, the whole of the US retail sector sold $2.29bn on Cyber Monday last year.
Alibaba's Twitter feed Alizila has been keeping followers updated throughout the day:
It's not only Alibaba that is expecting to have a bumper day - virtually all of China’s ecommerce sites such as JD and Amazon China are taking part in the sales bonanza, offering widespread promotions and discounts in the hope of breaking new records.
Here is how Alibaba's target compares to previous years: