How to Think about Parallel Programming: Not! by Guy Steele is a deeply interesting presentation on how not to approach parallel programming. The central theme is that languages should provide parallelism transparently, without programmers having to think in parallel.
Parallel processing of topic maps is another way to scale topic map for particular situations.
How to parallel process questions of subject identity is an open and possibly domain specific issue.
Watch the presentation even if you are only seeking an entertaining account of my first program.