Update Now Obsolete And Microsoft Update?

in my start menu -> all programs there is windows update and another called microsoft update. the icon for the windows update is the usual blue globe with the windows (4 colours emblem, its the one on your "start" button) and the icon for microsoft update is an image of a computer and an arrow pointing downwards.

in IE service pack 1, i clicked on the windows update on the tools tab on the menu bar. this loaded an empty page of the browser. this is the same when i click on windows update on the start menu -> all programs.
however when i click microsoft update, it takes me to the update page where i could download my service packs and 'express' and 'custom' installations. i traced the application which triggers the windows update and its from the system32 = wupdmgr.exe. i traced the application which triggers the microsoft update and its also from the system 32 = muweb.dll,LaunchMUSite. is the windows update now obsolete, unusable and just but a dead-end function. and is microsoft update now the site that replaces the what-used-to-be windows update?