• software development companies that build software products to assist their businesses' nondevelopment facets (such as finance and customer relationship management),
• non-software development companies that build software products to help their businesses' core facets (for example, an engineering firm that develops an application to assist with engineering), and
• software development companies that build software products to assist in their businesses' development facets (such as tools for testing, issue tracking, and so on).
• You might think you can bypass those other schemes because you've got internal users, which actually makes dogfooding dangerous.
• You might not address problems you've found because these aren't "paying customers," which makes the rationale for dogfooding specious.