I'm looking to compare how much money is made with Linux, vs. how much is made because of it. While I know it'll be hard to find the former and impossible to determine the latter, I think comparing the two will still be revealing.

What I'm looking to do is unpack the a distinction Eric Raymond began making many years ago, between sale value and its use value. The number that matters most, of course, is the latter. Even if it's not entirely measurable, I'd like to see some ideas about getting close.

Got some?