program selection system

What does it mean to be agile? What is lean and how does it relate to agile? How does our definition of agile evolve? How do we learn and adapt as a community and as an organization (the Agile Alliance)? What about these new ideas: Behavior-driven development, Kanban, Real Option Theory, and others? Are they agile or not? What about older ideas like Evo and Spiral? Do we measure agile and agility by the observed practices or do we look to values, principles and underlying paradigms that agile (and Lean) have sought to change?