Hi, I'm new to this forum.
It's interesting that I stumbled on the backmasking thread. I have looked into backmasking extensively, and I have some opinions about it. My first exposure to it was from Assemblies of God evangelist John Muncy. I heard a tape where he played many songs backwards, but he told you what the backwards message was before you heard it. So I always thought that was a bit deceiving since he already deciphered it for you. However, I started listening to other songs backwards and came up with my own interpretations. I found Satanic messages in some of them without being told what they were before listening.
I'm a musician, and I decided to listen to some of my band's songs backwards to see if we had any backmasking. We did! Some of it was unclear, but other parts were crystal clear. We had one song that said backwards, "I want you to believe in this, I'm born again, I'm saved."
My theory on backmasking is that somehow, our subconscious mind works forwards and backwards, so sometimes a song can say something intelligible both directions. I don't think it's because of a supernatural influence directly. But if there are Satanic messages, it's probably because the artist has some connection to Satan worship or the occult, which Led Zeppelin did. (They lived in the home of a deceased Satanist.) I don't think the Devil inspired Robert Plant to say things like "Oh my sweet Satan, the one whose little path, it makes me sad, whose power is Satan." I think this came out through his subconscious, just as backward messages came out through our songs.
Backward messages really just show where an artist's heart lies.