For a good example of the uses of
wire wrapping, see the wonderful book
The Soul of a New Machine by
Tracy Kidder. In it, he
chronicles the development of the
Data General Eclipse MV/8000 computer, code-named
Eagle.
In the book, engineers working on the new machines take turns wire-wrapping boards and debugging them when, inevitably, the various nasty (and sometimes highly amusing) faults of a developmental box surface. bitter_engineer's excellent description in fact made those scenes from the book clearer.