Why Do They DO That?

We went to a John Prine concert last night. I enjoyed it. The crowd was full of fans. Just one little question. What's with the WOO-OO shouted by people in the audience at really odd times. I can see excitement after a song is finished, or after a really active, long music segment, but in the middle of a line of a song (and he didn't mention some place anyone lives, or a type of car they might drive). I was really wishing for a very large roll of duct tape and thinking about all the things I could do to the WOO-OO'er near me. It could have had something to do with the beer supply in the lobby - that was the conclusion of the teenager sitting next to me. It could have been a spillover of the excitement of the unusual Memphis snow fall. Either way, I enjoyed the music at my first John Prine concert.