Problematic Internet use (PIU) is one of the most notable of all Internet threats. Young people are one of the groups at particular risk of PIU. PIU has become a research and educational priority due to its scale and the accompanying shifts in the media pedagogy paradigm. PIU is also the subject of many discussions and raises many methodological questions. The goal of the present study was to highlight the scale of PIU, and its accompanying protective factors related to interests, emotions and offline time spent on developing hobbies and passions. The study was conducted in 2016 in Poland, among 663 school students aged 17.93 (SD = 1.46), by means of triangulation of quantitative research methods. The scale of PIU was determined using a shortened version of Young’s Internet Addiction test. Warning symptoms of PIU were found in 23.52% of the respondents (“yellow light”), whereas full PIU can be observed in 5.88% of the students (the results are independent of gender). Thus, the stereotypical view that PIU is common is not true. PIU is connected with negative emotions offline (mostly boredom and a lack of self-control) and too little time spent on developing passions and interests. PIU presents a challenge in terms of both research and prevention. Depending on the criteria adopted, the scale of young people at risk of PIU changes. PIU is connected with offline activities. Failure to provide effective media education (focused on strengthening self-control when using new media) and neglecting individual passions and interests intensify PIU. Further discussion of the key factors that would allow PIU to be more clearly determined is also necessary.