Mission diagrams clearly illustrate the key steps along the way to achieve your end-goal. All steps of the diagram lead toward that end-goal. Arrows in the illustration communicate this intuitively.
Arrows connect goals. We work our way through the Mission Diagram from left to right, completing goals as we go. We tackle new goals as we complete the ones connected to their left until eventually we arrive at the end-goal of our mission.
With very little explanation a Mission Diagram communicates what the mission is (end-goal) and how we will achieve it successfully (arrows and workitems along the way).
The emphasis of a Mission Diagram is to minimally communicate what's most important to get a mission successfully completed. It leans heavily on simple lines, arrows, and a few basic icons and grapical accents.
A person can glance at a Mission Diagram and quickly understand what can be worked on next and where there might be choke points, if any. No reading required.
Creators of Mission Diagrams can share them with a team of collaborators or publish their diagrams to the world.
People can copy shared missions and use them as "templates" to complete similar missions of their own.