The phenomenon of the privacy paradox states that people are concerned about their data, but do not behave accordingly by avoiding disclosure of personal data, for instance, when using social media. Since findings about the influence of privacy concerns on privacy-related behavior are controversial, the present study investigates whether social norms or individual privacy concerns provide a better explanation of disclosure behavior. Therefore, a social media app dummy was developed and the social norm manipulated by altering the amount and the sensitivity of information provided in a fictitious app user profile. Regarding social norm factors, the results of the online experiment (N = 42) revealed that only the sensitivity of the data in the dummy profile demonstrated a medium effect on the amount of personal data given by the participants. Considering individual factors, the less concerned individuals were about their privacy, the higher were the amount and the degree of sensitivity of the personal information participants disclosed. In addition, participants differentiated between sensitive or non-sensitive information when disclosing their data. They disclosed sensitive information significantly less often, regardless of the dummy profile they saw. Altogether, the study results do not support the privacy paradox and demonstrate implications for media education.