Two different ways to get the boards listing...why?
If 'boards' is clicked at the top, it opens a pulldown of sorts with a listing, whereas if it's clicked at the bottom, it goes to a separate page. This can get confusing, because if the former option is used, and one tries to use the Back button in the browser, it goes back to... whatever page on which the pulldown was clicked, without the pulldown! Wouldn't it make more sense for the link on the top to go to the separate page?
The Boards link at the bottom is useful when you're using a browser or device (such as a smartphone) that doesn't display the pop-down menu in a usable manner.
The top link is a fast way to get to the boards listing (it loads much more quickly than a link to a separate page), but it doesn't work for everyone. The bottom link gives the people whose browsers won't work with the fast link a way to get the board index, too.