White Space

By using margins, gutters and alleys you can space out elements on a page to create the right amount of breathing room for all your elements.

• Active White Space: Empty space left blank to better structure the page and emphasize different areas of content
• Passive White Space: Empty space around the outside of the page or blank areas inside the content that result from a poor design

Here is an example from Not Coming to a Theater Near You:
 

 
Here the user had total control of where the negative (white space) would be located. If you use a floating layout, you do not have much control over where the negative space is located.