Moodle maintains a detailed log of each action performed by a user. Each record contains data about:
Who (user) did
What (action)
When (date and time)
Where (IP address)
Given this trail of information, it is possible to perform two major monitoring tasks:
Reporting
Tracking
Reporting is mainly concerned with summary information of user activities. An example is the number of views of a learning resource in a particular course.
Tracking is mainly concerned with finding details about a subset of the data, such as an individual, an activity, or a course. An example is a pupil who insists he/she has submitted an assignment, which cannot be located. The tracking log will be able to shed light on this.
Moodle further offers Statistics mode, which provides a graphical summary about the number of hits in courses and the entire site.
If these monitoring facilities do not satisfy your hunger for usage data, you might consider using external web analysis tools such as web log analyzers...