Designing information systems with adaptation capac ities is a challenge of great importance to improve the appropriation of the system by the users. In th is paper we view visualized digital traces as a mea ns to support reflexive type coupling between the system and the user. We examine the way users make use of digital traces with the objective of identifying po ssible use invariants. This is an indispensable sta ge in the enrichment of a trace system. We present a case study of an instrumented collaborative situation t hat answers this question. This case study uses theoret ical and methodological tools from cognitive ergonomics that enabled us to integrate the subject s’ point of view in the activity analysis. This stu dy allows us to formalize four schemas of trace usage. We discuss these results with regard to the appropriation and adaptation of information systems . This leads us to argue that a trace-based approac h is promising for the design of adaptive information systems.