COMPUTER CLUTTER Another thing that helps clean out files

What are those little rectangles with arrows that pop up in a computer folder when you move your cursor to a particular title?  I think they may be called Tips.  Anyway, they tell the last date that I worked on something.  This can be a big help:

For instance:  One day over a year ago, someone taught me a new resume format for people who have been displaced by the recession.  I know the approximate date that happened in June, 2012.

When those little "tips" give me a date before late June of 2012, I'll compare that title with similar ones and probably push the earlier versions into the Recycle Bin pronto.