Social media are used on a daily basis by public administration agencies in interactions with the public. The benefits of this form of contact have also been recognized by the Police, which maintains fan pages on the most popular social media sites. However, to date there has been no deeper reflection neither about the legal grounds for public authorities’ social media presence, nor about principles which they should obey while running their social media profiles. Using the Police as an example, this article discusses the legal basis for maintaining profiles of public administration agencies in social media. Authors analyze the issue within the framework of existing law and the views of scholars and commentators, confronting them with the legal basis provided by the Police departments. The article presents de lege ferenda conclusions regarding the so-called soft law.