Column 2. This is the first column in the markup. This is the page's content.
Column 1. This is the second column in the markup. This is the left navigation. ..
Column 3. This is the third column in the markup. The "contentarea" wrapper round the three columns is floated left like the three columns, to force it to enclose the three columns. Because of this, no matter which of the three columns is longest, the footer sits below it...