A year ago, we posted a motion graphic report illustrating the history of Chinese taxi-hailing apps. Of the major contenders, Didi and Kuaidi barely survived after rounds of fierce competition.

Following four rounds of financing the survivors jointly announced an "engagement" on Saturday.

The merger was announced on Valentine's Day with Cheng Wei, chief executive of Didi, saying: "It is a gift to the Chinese people and our great journey is about to start from here".

Many users of the two apps have expressed concerns about the "marriage".

On China's Twitter-like Sina Weibo, some people asked whether coupons provided by the two firms are accepted by both sides and whether the subsidies will be reduced or cut completely as a monopoly develops in the taxi-hailing service sector.

An online survey conducted by Sina claims that, as of Sunday, 63.6 percent of users said they won't use the apps if coupon subsidies are reduced, while the remainder will continue to use them.

According to the two companies, the deal is believed to create China's biggest mobile platform for local transportation.

Jack Ma, founder of Alibaba, praised the move, saying it makes a contribution to the "mobile transport" sector.

"Internet plus transportation" will become a new Internet-based industry, said Ma Huateng, chief executive officer of Tencent Holdings Ltd.