Yarif Sade outlines the differences of physical and digital products, and how the boundaries are blurring.
Physical products have always been an extension of the human body (think e.g. the mouse). Software is an extension of our human mind, and he gives the example of the act of writing.
Yarif stats that with the internet of things (IoT) these boundaries are blurring. We have devices that track our physical activities, and record them into data bases. As such these physical products are not only an extension of our body, but become part of the software itself.
Here is the full article: http://productdesignmanagement.com/physical-vs-virtual-products/