The comment tool in Word 2007 is a great way to proof-read a report or thesis paper and make notes to yourself instead of writing them onto a sheet of paper.

Open your Word Document.  On the Ribbon click the Review tab, and click on the New Comment Icon.

 

Highlight the area where you want to create a note and Word adds a balloon linking to that text where you can add your notes.

 

After organizing my thoughts on this rough draft I choose the "Show all Revisions Inline" option.

This makes it easier to maintain the clean interface on the document.  Just hover your mouse over the noted text to see the comment.