Frameworks vs Libraries

Around 61:20 into Debug #43 Marco Arment and Guy English provide a really good definition for frameworks vs libraries:

G: A library fits into what youre doing, a framework changes the way you see the world.
M: You build things into a framework that is already established for you, whereas the library let's you build what you want and let's you call into the library for help...

I think that's a really important distinction to make. Now, if I can just to figure out what a Platform is relative to a Framework I'll be good at my job.