Poetry is possibly the highest
artform of them all. It strives to
create something -
meaning - out of nothing.
The most noble use one can put language to, poetry is the pinnacle of the evolution of communication, for it communicates vast amounts of meaning through small amounts of text.
It is the best medium through which to convey and experience emotion, because there are very few logical boundaries, little or no narrative and language is put to uses which sometimes contradict every day speech - much the same way that we do in our dreams, when our mind is free of the constraints of cultural preconditioning, the need for common sense and the imperative to use communication primarily for tangible needs.
Poetry reduces language to the point where it conveys meaning only and is no longer useful to communicate information - in this it is a product of and an aid to the development of human though and our ability to deal with larger and larger abstracts. Almost as soon as you have writing, you have poetry - and, in Homer's case, probably even before that.