What an interesting argument! Laurence Thomas argues that there is a black American imperialism. [Note: Laurence's site doesn't like the server this blog resides on. You usually have to click on the link, wait until you get a rejection message, click in the URL box, and hit enter. I've never seen it fail to work that way.]
Blacks in the U.S. tend to see blackness as something they have a monopoly on, such that Barack Obama isn't really black due to his father being from Africa and his mother being white. You might hear things like, "Immigrant blacks don't have our heritage, so they must not really be black." At the same time, hip-hop is one of the biggest cultural exports from the U.S., and blacks in the U.S. are having a huge impact on blacks elsewhere, while ignoring that Africa is a continent and not a country, smoothing over the huge differences throughout Africa to act as if all blacks are just from Africa (appropriating half-customs with no meaning in the process). A number of elements in this process resemble the cultural imperialism that larger American culture regularly engages in, so it's interesting to see him identifying some ways that the black subculture in the U.S. does similar things.