She might be African-American, Central American, Asian or a mix of those or a mix of those with white. He's got a word limit, so he said she's 'of color'.

leeneia, that may be true in that case (I haven't seen the article), but generally someone says that because they are talking about a range of "non-White" people. "Person of Color" is not a term of happenstance or convenience, it is a deliberate usage.

The implication, especially in a social worker's discourse, is that White people in that society are less disadvantaged. You can debate the fine points of whether that is true or not, but that's the distinction that's being made, and it's precisely when someone would want to use the term "person of color." The only other thing they could say that would have those exact same connotations is "non-White"—which because of its negation doesn't sound as good.