Many of the poems lines are written in two groups of trochaic tetrameter -- two sets of four feet, with each foot consisting of a stressed syllable followed by an unstressed syllable. This is a reversal of the iamb that makes up the standard foot in much of English poetry (and prose, when scanned). There is a great regularity to this meter, which gives a sense of falling, but there are also many regular moments where this meter is broken by leaving off the final syllable: "And so faintly you came tapping, tapping at my chamber door" (line 22). This gives a sense of emphasis and a sudden stop at the end of the line, like the suspenseful pause in a ghost story, thus giving a deeper sense of the macabre to the poem than a purely regular meter. The final aspect of this poem that comes under heavy scrutiny is its length. Considering nothing really happens in the poem, it might seem strange that its narrative continues for so long, and some critics have claimed that there is really no point to the poem's length. Yet an understanding of the poem's subject makes the length simply yet another tool for emphasis. The broken, falling meter and the strong witchcraft-like effect of the rhyme reflects the perpetual sense...

The poem seems to keep going over the same ground again and again because this is exactly what is happening in the speaker's own mind as he ponders about his lost Lenore. The raven's presence unsettles the speaker "Till I scarcely more than muttered 'Other friends have flown before - / on the morrow he will leave me, as my hopes have flown before'" (lines 58-9). Even in the explicit language of the poem, the speaker is going over the same past events in his head, and even relating these new events and circumstances back to his previous experiences -- i.e. his loss of hope. This makes the length a necessary tool to fully bring out the sense of the speaker's interior struggle.
Edgar Allen Poe is not, perhaps, America's greatest poet or author. It is unfair to discount him simply as a purveyor of horrors without any real literary ability. The surface impressions that "The Raven" leaves in the minds of the reader might be too strong to easily overcome, but it is worth the effort to delve past these impressions and truly examine the poem. In doing so, the reader is able to fully appreciate Poe and his poems for what they truly are.