A common use of technology in higher education is the provision of online course materials, invoking an investigation of the ways in which students engage with online course content, and how their participation changes over time. This is particularly necessary in the context of high absenteeism from lectures, where online access may be the only way in which particular students are engaging with the course. In this study, we examine large-scale patterns of attendance in class, as well as four types of access to online materials. We define two online behavioural metrics -- richness and evenness -- to capture the distribution of online behaviours within 255 courses, and examine how these change over time. We find that both physical and online attendance decrease throughout the semester, but the fraction of students present online is considerably higher than the fraction present in lectures. Students adapt their online behaviour, and rare behaviours disappear over time. It is important to consider how we provide content, both face-to-face and online, in order to ensure that as many students as possible are accessing this content in ways that we intend.