A lot of things clicked for me when I tried to wrap my head around the concept of money as debt. A debt to be paid by the rest of society to the holder, when he's in credit. Or a debt to be paid to the issuer if the holder's a borrower. I'm not going to pretend to understand economics in any great depth.
Thanks for your detailed reply, I was thrown by the communist thing, and missed your point almost entirely.
If you haven't read Debt, the first 5000 years, do. I've managed to misplace my copy -- aha! just found it -- but it's among the most fascinating books I've found in 25 years on economics. That, Niall Feguson's Ascent of Money (the guy is in many ways an ass, but this is a pretty good book), Nassim Taleb, Nouriel Rabini, Paul Krugman, Joseph Stiglitz, The Ordinary Business of Life: A History of Economics from the Ancient World to the Twenty-First Century (Roger Backhous) -- hardly a page-turner, but a very good compendium of 3000 years of economic thought, and Neal Stephenson's Cryptonomicon and Baroque Cycle have been very helpful to my understanding.
One of the values in these online discussions isn't the ability to convince others nearly so much as it is to hone and refine your own arguments. I'm not sure I'm even partially cogent yet, but I'm starting to stumble in a direction I like.
Thanks for your detailed reply, I was thrown by the communist thing, and missed your point almost entirely.