Its social-networking function "moments" is similar to Facebook's "timeline." It is a feed made up of posts by contacts, often featuring personal posts alongside photographs, articles, songs or discount vouchers.
The "red envelope" is another popular function. It takes the Chinese tradition of giving out red envelopes containing money as a symbol of good luck, and packages it in a 21st-century digital wrapper.
"My first glance every festival day is to see if there is any red envelope," said Lei Yu, 23, from Beijing who has more than a thousand WeChat contacts.
This user dependency makes WeChat a great platform to deliver news and ads, as well as to conduct e-commerce.
Thanks to corporate accounts on WeChat, major news organizations and companies can push news, ads and coupons to subscribers. Brick-and-mortar stores also allure customers to their WeChat presence.
Wechat launched an in-app store service in 2014, attracting the likes of e-commerce giants like JD.com right down to individual startups.
ADDICTION
The fact that WeChat is "stealing" time from many users has led some to wonder if China is gripped by a "WeChat addiction," resulting in less real-world human connections.
Many heavy users said they spend much more time checking smart phones than conversing with friends or families.
More than half of WeChat users check the app at least 10 times a day. A quarter of users check it more than 30 times a day, Tencent's report on WeChat users indicated.
One netizen, Mojito, turned off "moments," meaning not to share anything about real life with unintended contacts.
"I have finished 43 movies and 14 books in the past six months," Mojito said. "Now I focus on my own things and don't pay any heed to what others think of me."
Absence of supervision over what is shared on Wechat is also a concern. While it creates a network of people with a high level of trust, the closed space is ripe ground for the spread of rumors or fabricated news, said a Renmin University communication research paper.