The reason that the big content is on the right is that it is the most popular content, likely already read. The new stuff is on the left, and we want the eye to move across the page in the natural way to help promote newer and rising content.
focus Oh look, a big picture on the right.
down I wonder what that picture is about.
left and up Hey! Another picture!
down Part of another picture!
left and up What are these little things on the left? Meh, too small to my eye which have just scanned big pictures and headlines. Ignore.
weird left to right diagonal thing between 2nd and 3rd column as I scroll down
By throwing the big stuff on the right, we're also making people who jump into the site for the big stuff move their eyes across the content, which might prompt a click.
We've thought very hard about who our site is designed for and the path their eyes will take. The column hierarchy is designed for different groups of people looking for different content.