There are two bases for this rumor.
1. As a part of monetization.
2. Career may claim the special data fee for WeChat.
Tencent officially denied this rumor, and their CEO Ma also said that he is sickened by this rumor.Actually, their comment can scratch out the rumor of former one, but how about will be the rumor of latter ?
Some resources said that there is the evidence to indicate the possibility of it. The following picture is the data fee bill of China Unicom.
The bill of WeChat exists as the independent item in this list, so they think that it is the preparation of the special fee for WeChat by China Unicom. And the rumor is that China Mobile also consider to charge the special data fee for WeChat.
I don't think that they made a wrong guess. Because as I said before, Chinese mobile SMS was substantially negative growth in 2012, and it can be said that the one of reason caused by WeChat. So it's the natural thing that careers despise the existence of WeChat.
Which direction they will go? Coexistence and co‐prosperity? Sharing of the earnings? War? We have to keep attention to what will become this answer.