I think it all started with an article on AListApart.
It actually made alot of sense. Traditionally all the navigation is at the top of the page. So users who read alot of the content, end up at the bottom of the page with nowhere to go, and have to scroll all the way back up to the top.
With the larger footers, you reward the readers of the page with easy accessible links for further information.
I persoanlly like them.