Commercial income takes many forms and can either provide additional funds for nonprofit journalism organizations or even full funding. These include advertising and subscription, among others:
How to Evaluate Commercial Revenue as a Sustainability Strategy for Investigative Media Organizations, by Ross Settles, adjunct professor focused on digital media and entrepreneurship at the Journalism and Media Studies Centre of Hong Kong University.
A Free Entrepreneurial Journalism Teaching and Learning Toolkit (See description by Jeremy Caplan, Director of Education, Tow-Knight Center for Entrepreneurial Journalism, City University of New York.)
Reader Revenue Kit A resource with articles on a variety of topics, maintained by the American Press Institute.