Eminem is merely the latest exponent of that time honoured tradition....white boys (stealing ?borrowing?) paying homage to the current trends in black music.
This has been going on since Al Jolson used to dress up in black face to sing Mammie and there are innumerable later exponents, like Eric Clapton with the Blues and the Rolling Stones with the blues/rock and roll mixture.
The musical form that Eminem appropriated is Hip Hop, that decadent expression of inner city homophobia and misogyny which has gripped urban America for the past two decades.
As always, the white boys get to make a great deal more money out of the enterprise than the original exponents. Record sales are hugely higher as having some short arsed runt whining about the Hood is so much less threatening than when the same is done by someone you really do not want to share an alleyway with. It also allows the great majority, suburban teens being that in terms of sales, to identify with a culture they would actually run a mile from if seen in the raw.
He has had two seriously famous moments, one when his own mother sued him for libel. Given what he called her this might have been a decent case yet given what was true about her it probably was not actually libellous.
He also used Dido on one of his songs and this was the great break of her career. Such a pity that she is always singing a quarter tone flat....which rather neatly matched Eminem and his prediliction for declaiming his lyrics half a tone sharp.
His official fan site is here. a fan sire is here at EminemWorld, MTV has a section on the little darling here and Eminem Web has enough message boards and news to choke the most obsessed fan.