In Firefox clicking a link with your middle mouse button will open the link in a new tab (or window, depending on your about:config setting). IE 8 opens a new

In Firefox clicking a link with your middle mouse button will open the link in a new tab (or window, depending on your about:config setting). IE 8 opens a new tab on middle mouse click. A new tab is not identical to a new window, but does mean you don't lose your place on the HN page just because you clicked a link.