It is invisible just as air and airwaves while body and organ are visible. Each bodies can communicate in the resonance. Resonance does not exchange information but synchronizes between bodies. The resonance media will not exchange anything. It will create a new emotion, that is change the prevailing emotional space.
Emotion is a resonance of various feelings.
But too many feelings cannot create themselves into a good resonance. Be careful of a 'powerful' resonance because it should be fabricated by integrating variety of feelings of numerous persons into a monotonous feeling, 'resentiment'. Mass media is a device to fabricate 'resenmtiment'. The resonance cannot take place in too large radius of feelings. If communicative community does matter, the resonance must decide the size of community.