I recently discussed ways in which our modern English is neglecting the nominative.
At the same time, we also take the accusative and almost always assign it to some abject address.
After all, when was the last time you heard someone say "To whom are you referring?" I will wager that for every time you heard that you heard at least twenty sentences that went something like this: "Who are you talking about?"
The latter is grammatically grotesque, whereas the former is fine.
I realized this clearly because of my current employment, which has me surrounded by people whose second language is English. At first I wanted to correct some of their usages of the word "whom", when I realized that I had been the one in error.
So be careful, kids, and be sure to use "whom" whenever your interrogatory pronoun is the object of the sentence!