Mozilla Firefox is an open source, free Internet browser that is released and maintained by the Mozilla Corporation. The current version is 3.5 and is available for Microsoft Windows, Apple's Mac OS X and most UNIX-like systems including Linux and BSD-based systems. The source code for Firefox is available under the GNU General Public License, the GNU Lesser General Public License and the Mozilla Public License. Firefox now has around 22% of the browser market globally - in some countries, it has reached higher penetration rates. Version 3.0 of Firefox had over 8 million downloads on its release day - June 17, 2008 - and has earned the Guinness World Record for the most downloaded piece of software.
In March 1998, under significant fire from the growing success of Microsoft's Internet Explorer browser, Netscape released the code base for Netscape Communicator 4. Netscape had reached a point of market dominance in around 1996-97. The code release was seen as a rather last-ditch effort to ensure competition. The Netscape code was cleaned up and released as the Mozilla Suite - now known as Seamonkey.
In 2002, Dave Hyatt and Blake Ross eventually considered the Mozilla Suite to be too bloated and so worked on an experimental branch. On September 2002, they released a very minimal browser called Phoenix that removed most of the bloat from the Suite: the e-mail, USENET and IRC clients, the address book and calendar. Instead, they tried to ensure the best browsing experience possible. After releasing a few versions, the Mozilla Corporation ran into legal troubles with naming. The name Phoenix conflicted with that of the BIOS manufacturer Phoenix Technologies who had produced a browser called Phoenix FirstWare Connect. The name was changed in May 2003 to Mozilla Firebird. Unfortunately, a database server application had the same name. In February 2004, the name was changed for the last time, to Mozilla Firefox, and this name has been protected as a trademark.
Users can add customisations to Firefox through the extensions system. There are now many thousands of add-on extensions, as well as custom themes. Some popular extension include Adblock and Flashblock (for blocking advertisments, Flash and Java objects and other undesirable web annoyances), Tab Mix Plus (for changing the behaviour of tabs), DownThemAll! (to grab large numbers of files, especially images) and FlashGet (which integrates Firefox with third-party download managers).