Now that an increasing number of journalists and editorial offices make use of social media platforms such as Facebook and Twitter to research, break, distribute and discuss the news, social media guidelines are being issued with increasing frequency by news organizations that want to indicate to journalists what is and is not permitted on these platforms. This study investigates how Flemish journalists experience the sense and nonsense of these social media guidelines, focusing on rules that prescribe their behaviour on Twitter. Analysis of 20 in-depth interviews demonstrates that the majority of Flemish journalists find the introduction of rules concerning the use of Twitter unnecessary. The argument heard most often is that the journalist’s common sense should be enough to deal with the platform in the proper way. A number of journalists even find the rules a curtailment of individual freedom. Particularly guidelines concerning specific formal requirements – such as mentioning the employer in the Twitter bio and/or account name, or the requirement to only use one account – encounter resistance. The interviewed journalists are, however, favourably disposed to a list of non-enforceable recommendations. Based on these findings, the tweeting journalists seem to indicate that they themselves are able to both adapt their use of social media to fit traditional professional norms and adapt those norms to fit the media logic of the Twitter platform.