The school online is supported by Tsinghua University of the Ministry of Education (formal in policy), but it is also a bit smelly at present; Huada large-scale open online courses and Netease are engaged in commercial operations and have certain economic strength; It should be said that the above two are quite standard and good. Personally, as long as the courses are rich (many) and free. As for the certificate, whether it has gold content or not, it is "true" to learn by yourself. I really think the teacher speaks very well, and I also have financial resources, so I will spend money to buy a certificate as a souvenir to support the platform construction.