Indeed, there is only one known phenomenon whose effects do not necessarily drop off with distance: knowledge.
A real-valued effect will tend to diminish with distance, but a binary transition (such as in a bi-stable system) will not diminish. Knowledge spreading is just a specific case of such a binary transition (unknown → known). An example of a physical binary transition is a detonation wave in an explosive.
A real-valued effect will tend to diminish with distance, but a binary transition (such as in a bi-stable system) will not diminish. Knowledge spreading is just a specific case of such a binary transition (unknown → known). An example of a physical binary transition is a detonation wave in an explosive.