The articles analyses the penetration of social media through personal use into daily life and the relation of this phenomenon to national security. A survey of Lithuanian higher-school students aged 18-29 was conducted according to quantitative research methodology. Young people actively use social networks for various purposes (personal, learning, work, recreation). Statistically, each individual, aged 18-29, has personal profiles on four social networking sites, yet most often does not adequately evaluate and link the use of social networks with possible national security threats and risk factors. Less than two-thirds of young people have heard something of possible threats and risk factors; however, the impact of social media on national security is not considered significant. Thus, it seems that young people lack information about real threats presented by social networks to both personal data storage and national security.