The border defines the organisation. In an interconnected, network society, an organisational entity exist because of its connections. The question about what really forms the entity that you want to influence, becomes actual.
The same question counts for organisation with strongly defined silo’s (or business units or product groups). Which is the defining boundary? The silo or the collection of silo’s? And what is the value of that collection? The recent split-up discussions are the most cynical expression of this essential question. The outsourcing trend that is still rolling out, is another example.
When people talk about cross-functional teams and projects, they also answer the question (implicitly?).