It seems bizarre, but the who and w utilities say there are no users on my system.
My account  is an Active Direcotry account and sssd is running.

johe@ibis:~$ who

johe@ibis:~$ w
 10:09:26 up 16:47,  0 users,  load average: 0.60, 0.59, 0.48
USER     TTY      FROM             LOGIN@   IDLE   JCPU   PCPU WHAT

I guess this is known behaviour?