The (hopefully many) green blocks at the right side of the menue are indicators for when the pages, files or links behind the menu items were last modified. This may help you finding the most interesting and current information on this website. It is only a little gimmick, but … well it may be useful. It is at least for me. ;)
There are by the way several other functionality enhancements: menu items may now be collapsed for a better overview. The personal preferences are stored for the current session only, so when the browser is closed, the configuration is lost. Nice and senseless, isn’t it :).