The way I like to explain this is to start from an intensional definition of money as "something that has no value by itself but can be potentially exchanged for something of that value". And total amount of money in economy is the total amount of these things at a given point in time.
So when somebody creates an IOU trusted enough so it could be resold, they have effectively created "money" according to the above definition, because now that IOU can be traded _independently_ of the thing it was originally exchanged for.
I think what confuses lot of people about this is that creation of money is a 3-sided transaction, and we are conditioned to think of a market economy as a sequences of 2-sided transactions.
Also, what I find very funny, some libertarians want to impose government to only create money backed by a commodity, like a gold standard. Yet their fundamental axiom is to allow any two parties to enter (almost) any contract, in particular, allow them to create and resell IOUs. However, if the government has to enforce any contract that two parties can come up with, this is already giving too much freedom for the money to be created regardless of the actual commodities in existence, and regardless what the government does.
So when somebody creates an IOU trusted enough so it could be resold, they have effectively created "money" according to the above definition, because now that IOU can be traded _independently_ of the thing it was originally exchanged for.
I think what confuses lot of people about this is that creation of money is a 3-sided transaction, and we are conditioned to think of a market economy as a sequences of 2-sided transactions.
Also, what I find very funny, some libertarians want to impose government to only create money backed by a commodity, like a gold standard. Yet their fundamental axiom is to allow any two parties to enter (almost) any contract, in particular, allow them to create and resell IOUs. However, if the government has to enforce any contract that two parties can come up with, this is already giving too much freedom for the money to be created regardless of the actual commodities in existence, and regardless what the government does.