What is DropBox? - Why you should use it?
Think a second... You make an assignment on your PC or Laptop & a friend asked you to give it to him/her, what you would do? Bring a pen-drive? Copy all assignments into that & give it to your friend? or you would email him/her...
These things also can be done 10 years ago, so is there no revolution in it? To share a file you must have to email or to share a photo...