To further complicate things, you also have to count the _customers_ of the firm in question. Amazon made certain things cheaper, and there are probably at lea

To further complicate things, you also have to count the _customers_ of the firm in question. Amazon made certain things cheaper, and there are probably at least a few marginal businesses out there that can exist because of it. A similar argument goes for eBay -- there are probably entrepreneurs out there who make a living in part because they can use eBay to buy things. This includes obvious stuff like resellers, but also less obvious stuff like a business that just uses eBay products as one of many inputs.