What does "Majia's account" mean?

It means that one person has multiple usernames and passwords, which are generally used to log in to websites such as forums for trolling or posting advertisements. If you change the vest, it is still him.

Sometimes, in order to support themselves or scold others anonymously, they will register another account. This is called "vest". The source is the joke told by Zhao Benshan, "I can't recognize you if you put on a vest?" ”