There might not be a tangible exchange (e.g. cash changing hands); this doesn't mean that a transaction isn't taking place. It's never a case of 'free' - it wo

There might not be a tangible exchange (e.g. cash changing hands); this doesn't mean that a transaction isn't taking place. It's never a case of 'free' - it would be more realistic to refer the phenomenon as 'zero-purchase-cost'. e.g. Facebook isn't free - users pay with their attention.