Learning to be tolerant is important in multiethnic societies. Based on the premises that tolerance is built through dialogue and that nowadays much informal learning takes place in social media, this paper explores the reactions of young people when they receive racist memes through social media, and how they dare to express their opinions(or not). Responses of undergraduate students to messages presented in print and Facebook were compared using quantitative and qualitative techniques. Quantitative analyses took into consideration their perception of each medium, their self-efficacy, and the amount of invested mental effort. Results showed significant differences in perceptions of each medium, as well as the percentage of students who chose not to respond (26.8% did not respond in Facebook). Using qualitative techniques, a variety of strategies to express or avoid opinions were identified. In order to confirm the identified strategies and investigate further reasons for not responding, the study was replicated using a class discussion forum simulating an instant messaging group. Reasons for keeping silent were categorized. Discussion of the results found refers to the need of including the interaction of sociocultural variables with cognition and media affordances in the theory of media research, as well as to the implications for the learning of values and interculturalism.