The ways in which I understand and appreciate rap as a poetic art boils down to its fundamentals: rhymes that stretch the boundaries of formal linguistics. Although I concede to the fact that a lot of rap artists employ explicit language and content to add gritty pizzazz to their lyrical arsenal, judging the quality of their prose solely on the merits of vulgarity disregards the contexts in which it derives from. It's quite ironic to find comments that generalize rap as just “speaking over a single drum beat” on a forum dedicated to appreciating the nuances in music. Producing a hip hop beat goes beyond simple and repetitive sampling of bars; a typical (not exceptional) beat is an amalgamation of 10-20 layers of (often unique) compositions accompanying a sample, if any.
I can understand the notion of rap being non-musical for some, but the beats, relatively speaking, is the least important aspect of rap. As someone mentioned earlier in the thread, rap can be described as “percussive poetry” in the most musical sense. So then, what of the poetry itself? Rap is all about the lyrics, rhymes, and wordplay. The sheer level of linguistic technicality is simply unmatched in most other genres. Rap incorporates the same literary and poetic strategies employed by written and spoken poetry as fundamental as Shakespeare and Poe. The rhymes are often multi-syllabic, and every syllable acts as a musical note on a sheet which can be manipulated within the confines of the time signature. In short, it’s a composition.
Poetic rhyming is essential for the art (i.e., not literal). As Eminem demonstrated in "60 Minutes," nothing rhymes with the word "orange" exactly when taking the word at face value, but bending its enunciation, into two or three distinct syllables, creates an entirely new suite of expressions: o-range, door-hinge, por-ridge, o-ran-ges, sy-rin-ges, etc. This, to me, is the true art of rap where the creativity starts to take over.
And what of the rhetorical devices found in both rap and poetry? Alliteration (there are some songs that go through the entire alphabet), allusion, assonance (“you'll never slOw the mOmentum at any mOment, I'm about to blOw, killin' the flOw, slOw, venOm any oppOnent is gettin' nO...”), metaphor, repetition (akin to recitative in classical), personification ("I Gave You Power," Nas rapping as a Desert Eagle), onomatopoeia, and the list continues. Rap incorporates all these; its lyrics demand analyses. And this is only the technical aspect of rap, which I’m obsessed with. Writing rap verses turns into a fun puzzle for me in this way, trying to convey a message in as many rhymes with words previously thought impossible.
Sure, mainstream rap tends to glorify the superficial, but I still enjoy listening to some of them for their fun delivery and catchy (but often shallow) rhyme schemes. The content matters not to me for these and I just concentrate on the technicalities. As much as I love and appreciate the complexities in classical genres, there are times that I just want to listen and recite to something fun, mindless, and even silly. It’s the classic underground vs. mainstream paradigm, akin to owning HD800 for critical listening vs. HFi-780 for casual/fun listening. I won't even go into the intelligent, socially conscious, or even experimental aspects of rap (the likes of Lupe Fiasco, Immortal Technique, and Deltron 3030, respectively) that are both technical and lyrical on a whole new level.
I apologize for the long post; I’m just very passionate about hip hop.