Effective Use of White Space

In the print publishing business, white space refers to the actual space on the page that is white.  In the web publishing business, white space doesn't necessarily have to be white.  It can be the background color or even the background design.  

Like a printed publication, leaving some white space helps the professional image.  Clutter is simply clutter, no matter the medium displayed. 

Conversely, be careful that you don't swing to the other end of the spectrum and end up with a site that's mostly white space and little content.