Jonesing, Snus is pronounced snoose. That is why you thought your grandfather was saying snoose, he probably was, lol.
Snus is very similar to dip, but it is different. I have never used actual snus, but from what I hear about it, it is kind of like a clay type stuff that you take a pinch and mold it into a shape and insert it in your upper lip.
I am pretty sure that snuff predates dip. I know that people were using snuff a long time ago. Napoleon used tons of snuff.
Chew on the other hand has probably been done since tobacco has been founded. I have no proof of it, but I imagine that people were probably chewing the leaves before they learned to smoke it.
I have tried the Camel Snus. It was OK. People that I have talked to that have tried real snus (which is commonly referred to as Swedish Snus) say that Camel is nothing like real snus.