This paper tackles the problem of understanding whether Self-Regulated Learning (SRL) is taking place and whether students are developing SRL abilities in a Computer Supported Collaborative Learning (CSCL) environment. To this end, the authors propose a taxonomy of indicators based on Zimmerman's learning cycle model, with several adaptations derived from subsequent research on SRL in Technology Enhanced Learning Environments. These indicators support the identification of SRL-related events in CSCL processes and have been tested in an experimental setting (the online component of a blended course for teachers) to analyse the messages exchanged by the learners. Content analysis was carried out manually by two coders on a sample of messages. The results of this descriptive, exploratory study are illustrated and compared with those previously obtained with different methods. (Contains 4 figures and 2 tables.)