In the Iranian legal system, based on the principle of privacy and general rules of responsibility, the principle is that online platforms are not responsible for the actions of their users. Obviously, all instances of loss due to the actions of users through platforms are subject to the rule of liability on the premise of the community of steward and cause, and the application of this rule imposes responsibility on the steward (user) unless the cause (platform) is strong. The criterion of an optimal legal system in the field of civil liability of platforms is the criterion that strikes a balance between the two interests of freedom of expression and the restriction of illegitimate content on online platforms. In Iran, obliging platform managers to review and select content for uploading will reduce content production due to managers escaping criminal liability risk. Also, in some cases, recognizing the legitimacy or illegitimacy of some instances of users' actions is complicated. Therefore, in cases of civil liability, by developing the concept of robustness of cause, where the platform intentionally commits a serious offense, it should be held accountable, and in the case of criminal liability, such liability should be exercised if the platform is malicious.