Concurrency is not Parallelism... Concurrency enables Parallelism

Here is a nice talk from Rob Pike on the subtle distinctions between Concurrency and Parallelism:
http://vimeo.com/groups/waza2012/videos/49718712


It's worth watching at least the first 20 minutes just to see the Gopher analogy.
After the first 20 minutes the focus is mostly on concurrency features in the Go language so it is only interesting if you want to learn Go.

At the end of the talk there is a mentioning of a blog post that says "Parallelism is not Concurrency", which is not the same thing as "Concurrency is not parallelism", but it is an interesting read nonetheless:
http://existentialtype.wordpress.com/2011/03/17/parallelism-is-not-concurrency/