This used to be a Southern thing - it has spread, which makes me kind of sad, as I miss being made fun of for it by my relatives in Kansas.

Here's a clue if a person is REALLY Southern - anyone these days will say "hey" in greeting, but if you are talking ABOUT greeting someone, and still use "hey," you are a true Southerner. For example:

"Let's stop in at Arlene's and say 'hey.'"

or

"Tell Aunt Jean I said 'hey.'"

or

"I just called to say 'hey.'"