Scrum exhibits fractal self-similarity, a property you can use to scale Scrum. Large organizations can deliver higher corporate productivity, revenues and agility in the face of rapidly changing markets. Everything scales, including the challenges.
We use a unique Enterprise Scrum process at Citrix Online (we are aware of no other organization using it) to manage a large, multiproduct engineering department. Anyone who cares, from the President on down, knows what engineers are working on, and has discussed and agreed on priorities.