There are two schools of thoughts about whether PM should or should not be a SME as well. In a more broader terms, should PM have technical expertise on the subject of the project. How in-depth of knowledge about product should PM have? Historically, in IT PMs were developers who were promoted to PM roles. As a result, PMs were SMEs but not necessary business savvy people. Nova days, PMs are frequently business people and not technical experts. What will the future trend be for PMs? Which knowledge will be most important, technical expertise or business knowledge or both?