The rapid release process has some positive side effects, like delivering new web technologies faster, and attracting world class developers who like to see their code ship fast. But rapid releases also have some negative side effects: minor annoyances with software updates suddenly become much more noticeable. Mozilla is experimenting with a Windows service approach that automates the software update process better without giving UAC prompts. There are four different Firefox development channels you can use: Release channel, Beta channel, Aurora channel, and Nightly builds channel.”]
Source: https://blog.mozilla.org/futurereleases/2011/10/04/mozilla-firefox-and-silent-updates/