Have you ever been away from work and thought, "I should be working on that project in Excel." Well if you save the document online through the Microsoft account, you can pull up saved documents from anywhere (with wifi, that is). Microsoft also has apps that can be used via your cell phone or tablet.
So now you can pick up from your last save and get to work!
Sources
http://www.makeuseof.com/tag/10-simple-office-2013-tips-will-make-productive/