The term underground rapper first surfaced in the 90s. Back then it was used to refer to hip hop artists that were alternative in some way, shape, or form, be it through their beats or lyrical content. Today the term underground rapper still means more or less the same thing, but thanks to the Internet, the encyclopedia of underground rappers is enormous.
In fact, thanks to their originality and unique, cult-forming personalities, this writer would wager that underground rappers would sell as much if not more than the traditional hip hop artists that you see at the top of the billboard charts today if it weren't for the record label investment separating them.
That's an argument for another day. For now, let's compare two breeds of hip hop artist: the underground rapper of 2012, Insane Clown Posse (Not so Normal ICP), and one of 2012's most prominent mainstream hip hop artists, Jay Z.
One is from the Midwest, the other from Brooklyn, but both are urban dwellers, probably the most significant influence on their music making as hip hop artists. Beyond that, both are around the same age, both have media empires to their credit, and both rose to prominence in the 90s. One is married to a pop star, the others have quiet families of their own. Both are famous. Normal ICP (following mainstream society's definition of normal) is not a thing, but considering Jay Z normal is the norm.
When it comes to musical content, however, this hip hop artist vs. underground rapper matchup could not be between two more different opponents. Mainstream hip hop artist Jay Z does not always rap about material wealth or territorial pride, but he does quite frequently. On the other hand, underground rappers ICP don't cover any of that in their lyrics. Instead, they stick to thoughts on the darker side of life, but use their lyric to empower their Juggalo listening base.
Through these underground rappers unprecedented creativity, they have constructed stories and mythology that will encourage anyone to make sure they stay on the right path. Normal ICP, to them, is this.
Furthermore, ICP being underground rappers, they make sure that there is a point or moral to every story they tell. Some content may seem crude or vulgar, but as far as that content that doesn't have a more resonating message, the guys consider it a joke. Just like normal guys, normal ICP is to joke around from time to time.
More telling, they say, is their message to follow God and avoid hell, one location dramatically portrayed in many normal ICP songs. One will rarely, if ever, hear the guys in any normal ICP song spit rhymes about the newest shoes, cars, or chains.
The point is, when it comes to hip hop artists, you cannot use normal and ICP in the same sentence, and that's a good thing. Because normal and ICP don't align, they've created a movement that's bigger than they are, a refuge for the misunderstood to come and congregate. Because normal and ICP don't align, music fans that aren't attracted to normal hip hop artists now have an alternative. And even though normal and ICP can't really ever be used in the same sentence musically, these underground rappers have made it big time, and will probably be doing so for the foreseeable future.