Research shows that multitasking implies that we use more time, remember less, learn less and perform worse than if we single-task.The article: ”Mobile Phones in the Classroom” (Kuznekoff et al. 2015) is worth highlighting as it is one of the most cited articles on multitasking. It shows how damaging written interaction is for learning in teaching situations. But does this mean that social media and written interaction should not be used in teaching? And that social media and written interaction only can harm learning? In this paper we provide a critical review of Kuznekoff et al. (2015). We argue that their laboratory experiment is taken out of real educational context and that this distorts the results they achieve. With a background in medium theory and media didactics we analyze the laboratory experiment and point out its shortcomings. Based on a qualitative real-life action research project we demonstrate that it is possible to set up conditions that make written interaction (through social media like Twitter) beneficial to education. Furthermore, we clear up the issue theoretically by distinguish between and discuss teaching situations in the new medium environment in relation to different kinds of concentration: diffused concentration (multitasking), non diffused concentration (singletasking) on one axis and the use of only one medium (singleplexing) and the use of several media (multiplexing) on another ortigonal axis.