Usage Tracking (at Setup > Usage Tracking) allows you to monitor the actual use of applications per user, per application, or per server. It also lets you monitor active sessions and the actual CPU load of an application. You can use this information to find users or applications that use a more than average amount of system resources, to re-distribute licenses, or simply for troubleshooting.
The Usage Tracking Viewer is available from Setup > Usage Tracking and from Diagnostics > Usage Tracking Overview. In the user session, the Usage Tracking Viewer is available from the Start menu > Workspace Control settings > Workspace Preferences > Other tab. The Usage Tracking Overview is available from Diagnostics > Usage Tracking Overview.