This study examines how students in Finland (16-18 years of age) constructed meaning and knowledge in a collaborative online reading situation. Student pairs (n = 19) were asked to write a joint essay on a controversial issue. First, the pairs discussed the topic freely to activate their prior knowledge. Next, they gathered source material on the Internet. Finally, they composed a joint essay. The data were collected using an interaction approach to verbal protocol data, along with video screen captures. In the analysis, three units were employed: episodes (n = 562) for describing online reading practices; utterances (n = 944) for identifying collaborative reading strategies; and collaborative reading patterns (n = 435) for clarifying how the student pairs constructed meaning and knowledge. Collaborative reading patterns were categorized according to a four-part model. A hierarchical cluster analysis was conducted to identify students' collaborative reading profiles. Five collaborative reading profiles emerged: co-constructers (two pairs), collaborators (two pairs), blenders (six pairs), individually oriented readers (four pairs), and silent readers (five pairs). Overall, it appeared that some students were capable of working in pairs, whereas others had a stronger preference for working alone. Collaborative profiles might offer teachers both an evaluative and an instructional tool to support collaborative interaction in their classrooms. (Contains 2 figures and 7 tables.)