This paper focuses on the relationship between politics and communication through social media. The empirical research asked about the significance of this relationship in the context of state agencies of Spanish Central Administration being the work in Facebook and Twitter the reference. The eminently applied observational context does has its hypothesis, such as the relevant quantitative extension of the audience in such social networks, such as the non-existence of a strategy. Beyond this second hypothesis, the work points to the potential dangers for the relationship between the State and citizens of its possibilityThe aims were to know the audience produced, to identify the existence of public policies of concrete communication with respect to these social media, and to establish the main dynamics of public opinion, perception of interactivity and citizens participation. In order to get those objectives, an online methodology of observation was designed, complemented with qualitative interviews to five community managers, and three focus groups. It is observed that the audience reached by the sum of all Facebook and Twitter accounts registered is greater than that of most Spanish media. The size of the audience of every state agency is conditioned by the social representation of the state agency, the integration of social media in the state agency communicative policy, the contents interaction whith receptors tastes and their daily life, and by the interactivity between organisms and citizens in the social media. The citizens discourses reflect a low sense of democracy in the relationship with the social media accounts of the state agencies. [ABSTRACT FROM AUTHOR]