The research is intended to prove the relevance of a writing for social media supplement to the ESL university-level course. Currently, the context in which language training is performed, features the stage of information society development where one has to generate, distribute and handle information efficiently in order to succeed in their professional activity. Progress in information technology as well as communication services and tools impacts the way people think, study, interact and collaborate. A variety of social websites, services and applications such as Facebook, LinkedIn, eBay etc. has become pervasive and ubiquitous. In addition, English is lingua franca of modern e-communication. Writing for social media in English is an expertise students should master to be successful in their social and professional communication in the 21st century. The paper provides the analysis of statistics of the use of English in social media discourse and results of Southern Federal University students interview about their attitude to the respective course supplement to be developed and implemented as part of the ESL curriculum. Consideration is given to the concept of social media, the phenomenon of virtual language identity along with linguistic characteristics of social media discourse being a hybrid verbal behaviour, viewed as a mixture of speaking and writing activities. The authors also focus on the main peculiarities of social media discourse to be taken into account while developing a writing for social media supplement as a plug-in to the ESL university-level course. The supplement is intended to help students develop and improve their communicative competence in the given area.