Who's That?

I've been seeing a trend lately.  And I can admit I have fallen prey to it as well.


When referring to people, use "who."
When referring to objects, things, or non-people, use "that."

The magician who started the show is known as an illusionist.
The illusion that made him famous was the apparent disappearance of the world's tallest hotel. 

When all else fails, remember - Who Are You?