Many papers report and convey positive opinion about the use of e-learning in the healthcare sector. The issue is how to exploit at best such a powerful instrument. Starting from data regarding the usage of a CME e-learning course, attendance dynamics and users' behaviour have been inspected with the aim of getting some hints about how to improve the development and the delivery of e-learning courses for CME, and to promote knowledge acquisition at best. The different paths followed by 7811 users have been modeled, from enrolment to conclusion/drop-out, then the behaviour in terms of effort, elapsed time, achieved result have been analyzed. The obtained results point out: good acceptance (retention rate 83%) of a not basic educational model and effectiveness (success rate 79%). At the same time the inspection of behaviour has shown that there is a good margin of possible improvement in terms of knowledge acquisition. Conclusions provide a list of issues to keep in mind during system development, in order to provide CME e-learning meeting both credit and knowledge acquisition goals.