Sourcing is the ability to evaluate information by analysing source parameters such as author's expertise on a given topic. Past research, mostly based on school-related materials and tasks, shows that adolescents do not pay attention to source parameters when evaluating online scientific information. However, recent research has suggested that such a 'lack of sourcing' may depend on the purpose for which information seeking takes place. The present study sought (a) to elicit the contexts in which adolescents seek information in their daily lives (included, but not limited to school-related assignments) and (b) to test the assumption that their attention to information sources depends on the purpose of their search. Focus groups were conducted with small groups of teenagers from contrasted socioeconomic backgrounds in two metropolitan areas (Rio de Janeiro and Paris). Five main contexts were identified, ranging from school assignments to monitoring topics of personal interest. Consistent with our assumption, references to sources were more frequent in personal compared with school information seeking contexts. The results suggest that researchers and science educators who wish to develop sourcing strategies among adolescents should use a variety of tasks, building on students' experiences of sourcing in daily life.