Paul Mooney famously once said, "Everybody wants be a nigga but nobody wants to be a nigga," which is about the most true statement in the history of African American culture. People LOVE black culture, but hate the folks who make it. If only there was a way to enjoy all this good black stuff without the pesky black people. And hence, appropriation was born. But it's not always Pat Boone taking the funk out of Motown or Elvis making "hip thrusts" white people friendly. Today, appropriation is more of a comedy art form practiced by hip hop loving white people who want the thrill of saying the "N-word" but not that pesky backlash afterwards.
Here is a brief compliation of white appropriations in black culture (particularly hip hop and "ratchetness"), and what these appropriations mean.