Course Site is equipped with robust reports that allow you to view various actions within your Course Sites.
To access the reports, goto Administration>Reports.
The Logs and Activity report are probably the most useful.
Logs allow you to run a report based on all participants or a certain participant, a date, an activity, and action, and gives you the option on how you would like to view the report.
An activity report simply gives you a snapshot of how many times a particular item on your Course Site has been viewed.