FYI, apparently doing that (making a P2P system to offload your links to the users) is illegal in China.
>Due to the proliferation of P2P CDN (or PCDN for short), which includes a large amount of home broadband uplink bandwidth at the central office, increasing operational pressure, and cannibalizing the traditional CDN business revenue share of telecom operators […] access is technically detected If the user's traffic volume exceeds a certain threshold, the speed will be limited or even the user's Internet access service will be interrupted. If the user finds a complaint, the user will be required to ensure that he or she has not used or removed the PCDN corresponding access device in exchange for restoring normal access. access services; thereby preventing access users from overusing home broadband and infringing on the interests of telecom operators.
>Due to the proliferation of P2P CDN (or PCDN for short), which includes a large amount of home broadband uplink bandwidth at the central office, increasing operational pressure, and cannibalizing the traditional CDN business revenue share of telecom operators […] access is technically detected If the user's traffic volume exceeds a certain threshold, the speed will be limited or even the user's Internet access service will be interrupted. If the user finds a complaint, the user will be required to ensure that he or she has not used or removed the PCDN corresponding access device in exchange for restoring normal access. access services; thereby preventing access users from overusing home broadband and infringing on the interests of telecom operators.
https://zh.wikipedia.org/wiki/內容傳遞網路#P2P_CDN