I read the words. I know what the words mean. I have no idea what the article said.
Imagine you kept a little black book with the names and numbers of all the hotties you had ever met.
Imagine you have a secretary (also hot, I did say "Imagine you have a secretary" after all) whose job it is to keep a second copy of your little black book in case anything happens to it.
One day, you spill coffee on your little black book, ruining all of the information in it. Fortunately, your secretary has a second copy of all if that information. Unfortunately, I said she was hot, not smart, and she dutilfully spills coffee on her copy as well.
Keeping a second copy is a useful way of protecting data. But if the first copy is corrupted, and you simply replicate that corruption to your backup....