This is a big step towards implementing silent updates in Firefox. Finally, Mozilla team has successfully removed the User Account Control (UAC) dialog pop-ups on updating the Firefox on Windows platform. This experimental feature is now live in Firefox 12, which is currently in nightly channel.
Role of UAC
Usually when software update themselves, UAC pop-up appears to take the permission from the system administrator in order to change the files in “Program Files” folder of Windows. Any change in the “Program Files” folder requires administrative privilege on Windows. Hence, UAC pop-ups appear on every software installation or update.
You must have noticed that the Chrome does not show UAC pop-ups on updating, and hence it updates “silently”. To avoid UAC confirmation, Chrome does not install itself in “Program Files” folder. On Windows platform, Chrome installs itself in application data folder (like: C:Users<user name>AppDataLocalGoogle), as installing in app data folder allows Chrome to skip the admin privileges and UAC dialog pop-ups.
Although, Firefox will use a different way to implement background updates. Moreover, just UAC removal is not enough for the silent updates. There are many more requirements like compatibility of add-ones etc. I hope to see complete implementation of silent updates in Firefox 12 or later.