I'm a white guy who went to a middle class African American high school (the other white students hovering between 5-8 any given year, with my two brothers being part of that number), and thus rap is a big part of my growing up. I was in the 8th grade when the Message was really hitting big. I was in the marching band, and we used to have members of the drum team who would bring a beatbox to and from games, so most games in that 8th grade I head the Message coming and going from band games (the clean cut version - it wasn't until years later that I found out what people "did" on the station they just didn't care!
). For the 5 years I was in the band, I heard a great deal of what Swifty did blasted from the back of the school bus while traveling- Freaks Come Out At Night, Roxanne Roxanne, Doug E Fresh's The Show (my nickname for a few years around this time was Doug E Fresh, as my real first name is Doug).
If you were into rap at this time, I'm sure you heard this blaring out of a car speaker from time to time - the Cars That Go Boom!
I was also really heavily into R&B of the time, with acts like the Gap Band, Chaka Khan (let me rock you let me rock you Chaka Khan), Patrice Rushen, Cameo, George Clinton, Mtume, the Jets, Zapp/Roger, Klymaxx, the Pointer Sisters, Kool & the Gang, and Prince if you consider him only r&b. I consider him Prince music, his own category!
And a quick fortean bit of r&b: I always thought that Midnight Star's Freakazoid was almost a cult initiative, or a movement towards higher consciousness. The part of the song where where they seems to sonicly enter another world and the "Midnight Star" voice came on was particularly cool - and probably sounds dated and silly to modern ears.