BEIJING, Jan. 22 -- About half of China's population are now active users of mobile messaging app WeChat, which celebrates its sixth anniversary Friday.

WeChat, developed by Internet giant Tencent, swiftly gained 650 million active users living in or outside China within five years.

In comparison, the online social networking service Twitter gained 320 million active users within 10 years, microblog Sina Weibo got 210 million within seven years.

"My daughter taught me how to use WeChat to have video chats with my granddaughter," said Li Fayang, a 59-year-old retiree from north China's Shenyang city. "Unlike traditional phone calls, all WeChat services are free."

Like Li, many Chinese rely heavily on WeChat to communicate with family, friends and colleagues on a daily basis, via its text messaging, hold-to-talk voice messaging, six-second-video messaging and video conference services.

In addition, WeChat has a social-networking function called "Friend's Circle," similar to Facebook's "Timeline," encouraging users to share their moments with texts, photos and mini-videos. Users may also subscribe to public media accounts, organizations and companies for newsletters.

User dependency cultivated through such well-received free services makes WeChat a golden platform to deliver news and ads, as well as to conduct e-commerce business.

WeChat launched its mini-store service in 2014, offering platforms to big and small business operators. Major online commerce companies including JD.com as well as millions of individual start-ups now all take advantage of WeChat platforms to do promotions and direct sales.

Shen Yue, for example, a 23-year-old Chinese student who lives in the United States, manages to sell homemade cakes on WeChat, mostly to her Chinese friends and friends of friends living nearby.

While WeChat is bringing fundamental changes to people's lives and business modes, there are concerns about the "WeChat addiction" that is distracting people from their daily lives.