Having lived in both Canada and the USA, I can say from personal experience that Canada is a much less racially polarized society than the USA is.  That said, I really find most of the comments here (even most of the "highly rated" ones) to completely miss the point about what constitutes white privilege.  While in a minor sense, the example used in the article (the grocery store) can exhibit privilege, that is not the issue.

The issue, at least in America, is that (a) black students in schools are targeted for disciplinary actions, leading to arrests, in situations where the same behavior by white students is overlooked; (b) black drivers are given traffic tickets when white drivers are given warnings; (c) black defendants in court are given prison terms when white defendants on the same crimes are given probation.  This is compounded by discrimination by employers based on what appears to be a black name.  

See Part 2.