I love listening to Gabe talking about Gamification and what it is and what it is not. Around 11.00 minutes he states what is not.
As teachers we are often in a situation to review a document. This might be an assignment draft or a document a colleague has askeed you to to look over.
Either way, any of your edits can be lost if the changes have not been tracked.
Here is a great training video (the first 4 minutes is all you need) that outlines how to use the Track Changes tool in Word.