"The Listeners" tells the story of a traveller who arrives, late at night, at an isolated house. The traveller knocks repeatedly at the door, but nobody answers. The fact that nobody answers is strange for two reasons. The first reason is that the traveller seems to have been summoned to the house, as indicated when he says, "Tell them I came." The second reason is that there are spirits inside the house who choose not to answer the traveler's insistent demands.
The title of the poem indicates that the mystery of this story is not so much about the identity of the traveller, or the purpose of his journey. Rather, it is mostly about the identities of "the listeners." These "listeners" make "Never the least stir" while the traveller knocks at the door and shouts for admittance. They are described as "phantom listeners," and it is implied that the house that they occupy belongs to another, spiritual world. Indeed, describing the listeners listening inside the house, the traveller's voice that they can hear is said to come "from the world of men," implying that the world inside the house is not the same world the traveller comes from. By indicating, in the title of the poem, that the central mystery pertains to the identities of the "listeners," the poet also shifts the focus of the poem to the supernatural and the spiritual, rather than the everyday and normal occurrence of a traveller arriving at his destination.
The title of the poem also indicates that the eponymous "listeners" are listening for something. In the poem they are described as "listening in the quiet of the moonlight." The title thus immediately makes the reader wonder as to what exactly the "listeners" are listening for. If they are listening for the arrival of the traveller, who has been summoned, then why, we might wonder, do they not answer? What is the purpose of their listening if not to answer the calls of those who have been summoned? At the end of the poem, after the traveller rides away, the silence is described as "surg[ing] softly backward" into the house. The implication here is that the return of silence is a relief for the "listeners," and this increases the mystery even more. If the "listeners" are listening so intently, we might wonder, why do they seem relieved when silence returns?
In summary then, the title is significant for two main reasons. Firstly it indicates to the reader that it is the "listeners" who are the focus of the story, rather than the traveller. Secondly, the title is significant because it introduces to the reader the central mystery of the poem, namely the question of what exactly the "listeners" are listening for.