What would be the difference with copyrighting online compared to having it by snail mail?

I also heard of a notre republic from a bank. If I have the name correct.
Maybe copyrighting and publishing have more to do with how much information is lead back to the originator.
I know people that want to copyright inventions instead of songs.

All this information and if it becomes profitable, a lawyer to hold it in place.
But I know that would be too simple.