You’re at the coffee shop. You need to access a file that has information about your work, but as you attempt to find the file you realize that you’ve made a mistake. You saved the work on your desktop computer, but you only have your laptop with you. You have no way to access the file. This problem, and others like it, are increasingly common today. It isn’t unusual to own both a desktop and a laptop computer, and a smartphone on top of that.