Something most white people would never pick up on without help is that it's sometimes insulting to compliment black people. In particular, it's insulting to say something nice about someone who is black that you wouldn't say about someone who is white. Such a compliment assumes that it's surprising that this would be true of someone who is black. A good example is the common practice among media types to speak of certain black people as articulate (see Mixed Media Watch for an example). How often do you hear white people being called articulate? I don't think it's all that common. Pay attention, and you'll discover that it's a good deal more common with black people, especially young black men. I've never heard a young white politician being called articulate, except I think in the case of one who happened to be a teenager, where there might be less expectation for such a thing. But Barack Obama, J.C. Watts, and Harold Ford, Jr. get it all the time. You don't generally hear it of professors of linguistics, unless it's John McWhorter. You won't hear about economics professors being articulate, except when it's Thomas Sowell.
Now I'm loath to call this racism without explaining more carefully how I'm using that word. Such a statement would be received as nonsense by most white people, because most white people (indeed, most English speakers) use the word 'racism' to refer to a deliberately negative attitude, and that's not what's going on here. This is why academics who specialize in race matters have come up with terms to describe this sort of thing to distinguish it from the more standard and obvious cases of racists. This is unintentional racism. It involves racist structures in society. It involves residual effects on the attitudes and actions of well-meaning non-blacks. But I think this is a case of that sort of racism, at least generally. See MW's comment in the Mixed Media Watch post for good reasons to think this is often a kind of racism even when you don't think it is.
This is something I've been aware of since reading John McWhorter's Losing the Race. As I said, it's not the sort of thing that most white people would notice otherwise, even ones who are more sensitized to these general sorts of issues. I paid attention to when I heard the word after I read McWhorter's discussion of the issue. What few occurrences I encountered did seem to fit the mold. But then a few weeks ago I heard someone call Ann Coulter articulate. Does this refute the claim that calling young black men articulate stems from some kind of racism?