The Site Analysis tab is a historical representation of license usage. It shows you the max concurrent license usage for a given period.
You can set the period of time that you would like to see th data for under Period on the left-hand side of the page
Under type you can select either line chart or data as a grid
You can additionally filter the graph by project, user, and license type by clicking the Filter button at the bottom right of the tab
The Site Analysis tab will not show you the users that access the application it will only show you concurrent license information for a day, week, month, etc. If a user logs in three times in a day only one license was used on each login so the graph would show one license in use for the day. If two users are logged in to ALM at the same time it will show two licenses in use concurrently for that day. If after the two users log out a different user logs in and then logs out it will still show two licenses because only one license was in use.
Additional information on how to use the Site Analysis tab can be found at...