Taobao found that regions such as the Guangxi Zhuang autonomous region in Southwest China - where e-commerce companies are less sophisticated - have a significant number of "night fighters".

About 680,000 Guangxi residents belong to the "night fighter" category.

"That may be because the sunset in Guangxi comes a bit later than in other regions," the Taobao report said.

Meanwhile, another category - known as "hoarders" - might become very anxious if they believe that there's a small chance that some of their favorite products will be sold out, Taobao said.

The group, which comprises 1.3 million people, is the fifth-largest in the list. People in this category like to buy goods in quantities large enough to last for a year. Henan province has the biggest number of "hoarders", and they usually buy 98 of the same items at a time on average.

Also, more than 1 million people are known as "collectors". Those customers enjoy searching for antiques, paintings or stamps online, while others are addicted to collecting instant noodles with different flavors.