Path: utzoo!attcan!uunet!bloom-beacon!ATHENA.MIT.EDU!swick
From: swick@ATHENA.MIT.EDU (Ralph R. Swick)
Newsgroups: comp.windows.x
Subject: Re: Looking for a program like xtalk...
Message-ID: <8909251615.AA16406@LYRE.MIT.EDU>
Date: 25 Sep 89 16:15:12 GMT
References: 
Sender: daemon@bloom-beacon.MIT.EDU
Organization: DEC/MIT Project Athena
Lines: 11

> Has anyone at the Xconsortium
> thought about how to get the display an arbitray user is on?

not a lot, but Project Athena has.  See

  DellaFera, et. al, 'The Zephyr Notification Service',
  USENIX Conference Proceedings, Winter 1988, pp. 213.

The basic approach is to declare Yet Another Network Service
which is a database mapping (among other things) usernames
to displays.