If you're a Firefox user you might have noticed that updates come much more frequently these days. That's because Mozilla has decided on a six-week cycle--for major versions. Firefox 6 was released six weeks ago on August 16. Today Firefox 7 is scheduled to be released.
Large organizations--at least those that aren't insane--don't roll out software to their users without some vetting, nor do they let users install whatever they please. A six-week cycle is much too frequent to allow for a reasonable test. Mozilla also has explicitly resisted providing a manageable installer (generally .MSI and .MST files for Windows), making it much harder to distribute the software, especially updates. But they had to do something, so Mozilla reactivated a long-dormant Enterprise User Working Group and worked with it to figure out what was possible. The discussions have led to an initial proposal for a more stable branch of development.
Currently, not only does Mozilla release a new version every six weeks, but it discontinues support for the old one at the same time. Under the proposal, every fifth version--starting with Firefox 8, then 13, then 18, and so on--would have a much longer life cycle of 42 weeks. Every six weeks when the major version revs, this version, called the ESR or Extended Support Release, would get a .01 increment version name, incorporating fixes for "...high-risk/impact security vulnerabilities and would also include chemspills (off-schedule releases that address live security vulnerabilities)." Chemspills. I love that.
It's only a small excuse for Mozilla that it was Google who started the whole crazy-short major version cycle problem. It's just a little over three years since their Google's initial pre-release version and it's up to version 14. Perhaps this is what makes Mozilla feel it has to move faster. But at least Google provides an MSI installer for the full version so you can push it out using group policy.
But it's fair to say Google also makes it hard for businesses to use their browser as an "official" browser. Every wonder why so many businesses stick with IE as their official browser? This is why.