To collect commodities are products that can be bought and sold. It refers to a useful quality or thing. Ideas make bad commodities because you can't know whether they are useful or not until you know them. The author is in favor of the democratization of knowledge (enlarge) because current developments such as the internet allow ideas to be available for everyone. So, saying that we are mean when dealing with sharing ideas is a contradiction against the present times and its advancements. Tagging ideas that are not your own.