Regarding introductions / explanations

I have noticed in various interviews etc, that a lot of songwriters are not always that keen on giving an answer to the question ' Just what is that song about ?' One of the interesting things about songs is how they can take on a life of their own. Somebody sits down to write a song maybe based on some incident in their own life or from events in the real world.They write it and then they perform it and maybe record it. Then anytime after that we hear it, we like it , it strikes a chord etc. We do not have to know what it was originally about unless we would like an explantion for a particular line or phrase. Song lyrics can appear pretty vague on the printed page but combined with the music and singing they can take on a 'meaning' for the listener.

If I can give one example , the song Hurt by Trent Reznor. I think I read somewhere that this song was written about heroin addiction. But then when you hear Johnny Cash's version ( and more importantly see the video ) the meaning of the song changes, it becomes about someone looking back over their life and actions or inactions.

The beauty of song.