What must the goods and/or services of a ‘For Profit’ firm do in order to assure an ongoing stream of revenue?

• What must the goods and/or services of a ‘For Profit’ firm do in order to assure an ongoing stream of revenue?
• What is it that the goods and/or services of a ‘Not For Profit’ organization must do in order to assure an ongoing stream of contributions?

In the end, what is the difference between the two types of organization?