I couldn't agree more that Microsoft Update should enable automatic updates of third parties. I don't agree that the reason they don't do it is due to legal issues. After all just give a blanket disclaimer to the end user, and force the User to choose
when they install an application whether it should be allowed to update itself (note that it should say how to do this manually from within the app, should the user choose not to). I write Windows apps for a living, and while Click-once addresses many of the
issues, there are still non-managed apps out there that bug the hell out of me wiht update requests (Quicktime/iTunes being the biggest offender with a massive popup while I'm working on something).