Lets say you got this nice little word document from a friend or colleague and stumble upon a word or words -like obiter dictum - that you do not know. How would you normally look it up ? You either pick up a dictionary or fire up your browser and search on the Internet for a definition of the word. This does not slow you down that much if it is only one word but what if there are more of them ? It could really slow you down unless you find a better way to lookup those words.