Rappers and Rock n' Roll (Two For One Special)

This may be simply ignorance on my part, but was anyone else aware that there are rappers in the rock n' roll hall of fame? I heard on the radio this morning that the group RunDMC (I hope that's how you spell it) was recently inducted and they aren't the first either. Grandmaster Flash was actually the first rap artist "allowed" in. The station was also emphasizing RunDMC's collaboration with the group Aerosmith, creating a mesh of rap and rock, which was deemed an ultimate success by about 90% of fans, and total blasphemy by the other 10% of die hard rock fans. I can't say I'd ever before heard rap or hip hop done with electric guitars, but then again, I don't make it a common practice to encounter much rap to begin with. :)