Google Desktop widgets can now be embedded in your iGoogle personal start page. This new functionality adds OS-level functionality such as CPU utilization, currently playing tracks in iTunes, or a battery indicator inside a Web interface. Google Desktop 5.5 is now available in a widget-only version for Windows 2000, XP, and Vista to bridge the desktop and Web worlds.
The decoupling of Google Desktop Sidebar puts its desktop widget platform in direct competition with Windows Vista Sidebar and Konfabulator. Google can use its widget platform as a beachhead onto the desktop and later encourage its users to enable more Google Desktop features such as search and personalization.
(Disclosure: Google is a sponsor of my upcoming widget conference, Widget Summit.)