The blog post (and long - only commodity index investing) is discussing part of systematic opportunities which have to do with the economic function performed by commodity futures markets. (indexologyblog.com)
It also brings gains in production, since it allows countries to manufacture only those commodities that provide them the best possible earnings. (religion-online.org)
Unlike stocks, which have a single letter abbreviation for each publicly traded company, commodities tickers must specify not only the commodity but also the delivery date and year of the futures contract. (wikinvest.com)