When I login to my Live Messenger, it required me to update. Sounds good to me to see any new updates.
After the loading screen there, it shows me some major updates on outlook connector (free add-in for Microsoft Outlook that allows users to access Windows Live Hotmail), office live add-in (do not know what it does) and silverlight (a programmable web browser plugin that enables features such as animation, vector graphics and audio-video playback).
I am still waiting for the 166MB update download which should take a while.