It depends on the settings of the platform or website where the stories are posted. Usually, the author of the story and anyone with the appropriate permissions or access can see the comments.
It really differs. For some sites, only registered and logged-in users can view comments. On others, it might be available to the general public. The specific rules for who can see comments are determined by the platform's policies and the choices made by the story poster.
Well, it varies. Sometimes it's only friends or followers of the author, while in other cases, it could be open to all users of the platform. The visibility of comments often depends on the privacy settings configured by the platform or the author.