Be explicit about which users have access to each specific dashlet. Enable or disable dashlets for certain types of users regardless of what their permissions are to that module. Gives finer control over the data available to a user from the home page dashboard.
Other add-ons of interest
Glances - Integrate All Your Applications
Accomplish More Every Day. Spend your time on getting things done, not on finding information. Glances securely connects all of your apps and provides a simplified view of the data you need right when you need it, in real time.
LogTrack is the best plugin to track the user login history. It stores the login and logout date and time, and the IP address from where the users logged in.