Reply to Most modern music is four minutes long. Thoughts on why?

Just did the math on my collection's song per minute ratio and found that the average was 4.05 minutes per track. I then looked up the average and found it to be almost 4 minutes exactly per song according to this web post.

http://www.statcrunch.com/5.0/viewre...47&groupid=948

In the comments section, I read that four minutes was about the length of your average 78rpm records, and that format availability may have had a contributing factor in the average length of today's songs versus what is most enjoyable. As a dj, I generally try to play a song for two to three minutes before transitioning to let the production do the talking, but keep the short attention span of the floor.

Thoughts?