> Maybe someone in this list can provide a good example of coroutines
> use?


For a neat illustration (and critique) of coroutines lookup:
"Experimenting with tail-recursion and simulating coroutines" -
http://doi.acm.org/10.1145/306286.306315

For those with a bent toward functional programming, there are
similarities with the trampolined style:
"Trampolined style" -
http://doi.acm.org/10.1145/317765.317779

Thanks,
-Bhanu