working link
'Jupiter Collaboration System' link goes to ACM which requires an account. Free version of paper is here (needs postscript, ghostscript reports an error but it seems harmless):
<ftp://ftp.lambda.moo.mud.org/pub/MOO/papers/JupiterWin.ps>
google textified version can be found easily enough but it lacks diagrams.
So - MS is the biggest software co in the world, and xerox commercial software production is nowhere despite their incredible legacy. There must be a moral.