It doesn’t work correctly or as it expected. Please have a look at the attached screenshot.
https://dl.dropboxusercontent.com/u/19702192/Screen%20Shot%202013-04-24%20at%209.12.57%20AM.png
It left all the bottom content without background.
Edit: I gave
#secondary {
clear: both;
padding-bottom: 50%;
padding-left: 0;
padding-right: 0;
padding-top: 50px;
background: #FAFAFA!important;}
and it seems fine. Maybe…