The powers that be seem to have decided that because the web is evolving and so is Firefox, that a rapid release cycle will be used; this is planned to result in updates about every 6 weeks. Hopefully this results in a few small changes, that are quick and well tested, rather than a major update with multiple changes and long waits between updates. See for instance http://blog.mozilla.com/futurereleases/2011/08/26/rapidity/ Often updates will include security fixes. In the case of the Mac there have been OS changes, and at least one additional update was for Macs only to cope with some of those changes. A particular problem recently was with certificates that were [http://www.us-cert.gov/current/index.html#fraudulent_diginotar_ssl_certificate hacked] . Firefox (and other browsers) reacted to the situation to try to resolve that issue whilst trying to minimise inevitable side effects. This subject is probably not on topic for this forum, but I can understand frustration at all these releases, especially when problems for instance with add-on compatability arise.