In Outlook, when I click the Address Book icon, the "Show names from the:"
drop-down provides several choices. Under the All Address Lists section of
that drop down, I see several things but specifically:
All Contacts
and
All Users

I only appear under the All Users list, but some of my co-workers show up
only under All Contacts. There seems to be no rhyme or reason between the
two. What is the difference between an Outlook Contact and just a User
anyway (as it applies to this listing I mean)? Contacts have a globe icon
and Users have no icon I can see so far.

Thanks in advance!