I think project portfolio management is fundamental for many organizations, and too many organizations manages project as distinct totally separate universe.  I even think that mastering Project Portfolio Management is more important than standardizing all project management tools and processes in an organization.

This is a good article on What is Project Portfolio Management”, on www.projectmanager.com (a SaaS Project Management app)

No organization has enough resources or time (isn’t time the most precious resources of all) to do all to perfection.

The end of the article is a nice summary:

What is project portfolio management? It’s the ability to choose, prioritize, execute, and report out on those projects that directly support the corporate strategy. It ensures that the ladder that everyone is working so diligently to climb, is not leaning against the wrong wall. Think about the project portfolio in a similar manner as your personal investment portfolio. You are looking for the right balance of risk/return that will help you meet your long-term goals. Adopting project portfolio management in your organization will help reach that proper balance!

Although many text including this one focus on return on investment and profit, even other kind of project must be aligned with the strategy of the organization, and maximize the proper use of its resources.