Lists, Useful For More Than Menus

I came across a page recently that uses ordered lists for the entire layout -- not just the menu. The entire layout is in two parts: one ordered list for the header/body/footer, and another ordered list for the three columns inside the body.

I find this to be an interesting approach to multi-column layouts. Better yet, the author claims that it works in all major browsers on the three major operating systems.

However, are ordered lists the proper elements to use in this case? Is it "semantically correct"? What about unordered versus ordered lists? It'd be terribly simple to convert the layout to work with unordered lists, but which is more "correct".

Regardless of correctness, though, "no floats, no divs, no clears" is rather appealing.