RE: How to tell who is using ST in our company William Hepler 16.Aug.11 05:06 PM Lotus Notes Administration All ReleasesAll Platforms
in STLog.nsf there are many, many views.
One of which should be Community Login/Logout's by User. This will show you every user that has logged in, when, and when they logout. You should be able to use Shif - to compress all of the expanded documents to get a high level view of users.
I believe there are other views such as Community Login by date also if you want to focus on a particular time frame.