The aim of this work is to show the duality in the use of social media by the Public Administration, once it can be useful to help the government to promote the on-line citizenship as a strategic objective, however it is not enough the use of them to guarantee the democracy, because they also must respect the citizens' rights such as the liberty of expression, by avoiding to block comments of the citizens which disapprove the government in the social media such as Facebook and Twitter, except when it is justified in case of offensive words or bad language used in the social media.Sociedad Argentina de Informática e Investigación Operativa (SADIO
