I don't believe that there is anything inherent in Plan 9 that
makes writing parallel programs easy, especially if the machines
in question are not shared memory machines.  We have a thread
library that is different, but not significantly so, from other
thread libraries.  Alef had constructs in it for parallel programming
but it died from lack of support/use.

The only thing we do have is an easy way to import resources from
other machines.  However it requires that the interface looks like
a file system and you can only push that so far.  It's been useful
for decomposing a larger system in to a bunch of servers that can run
on disparate systems/architectures.  However if you have to pass
messages twixt programs, it doesn't really help deciding what
the messages should look like or how to marshal them.