This study attempts to organize the regulatory perspective on the interaction between information law and competition law, especially for platform businesses. An online platform is an entity that mediates between multiple groups of users, such as providers and users of products, services, and information, and has an indirect network effect as a two-sided market. The study illustrates the actions taken by online platforms, indicates attendant problems, and suggests responses to these. Four aspects of the competition policy issues related to online platforms are analyzed and discussed: data collection, data enclosure, data acquisition, and algorithmic transparency. The study considers essential online platform issues, such as the promotion of competition policy and the issue of fairness in the application of information law, to deepen the discussion. It is noted that although fairness is important, there is a risk that the analysis of the effects of reducing competition are neglected and that the interpretation of fairness might increase the concern with over-execution. Having disaggregated the elements of fairness, the study suggests the need to establish specific standards.