Mozilla Firefox is a graphical web browser developed by the Mozilla Corporation, and a large community of external contributors. Firefox, officially abbreviated as Fx or fx and popularly abbreviated FF, started as a fork of the Navigator browser component of the Mozilla Application Suite. Firefox has replaced the Mozilla Suite as the flagship product of the Mozilla project, under the direction of the Mozilla Foundation.
Mozilla Firefox is a cross-platform browser, providing support for various versions of Microsoft Windows, Mac OS X, and Linux. However, the source code has been unofficially ported to other operating systems, including FreeBSD, OS/2, Solaris, RISC OS, SkyOS, BeOS and more recently, Windows XP Professional x64 Edition.
Firefox's source code is available under the terms of the Mozilla tri-license (MPL/GPL/LGPL) as free and open source software. The current stable release of Firefox is version 2.0.0.6, released on July 30, 2007.
According to Market Share by Net Applications, 14.55% of the world's Web browsers used Firefox in June 2007, with 13.92% using version 1.5 or higher.

History
Dave Hyatt and Blake Ross began working on the Firefox project as an experimental branch of the Mozilla project. They believed the commercial requirements of Netscape's sponsorship and developer-driven feature creep compromised the utility of the Mozilla browser. To combat what they saw as the Mozilla Suite's software bloat, they created a pared-down browser, with which they intended to replace the Mozilla Suite. On April 3, 2003, the Mozilla Organization announced that they planned to change their focus from the Mozilla Suite to Firefox and Thunderbird.
The Firefox project has undergone several name changes. Originally titled Phoenix, it was renamed because of trademark issues with Phoenix Technologies. The replacement name, Firebird, provoked an intense response from the Firebird free database software project. In response, the Mozilla Foundation stated that the browser should always bear the name Mozilla Firebird to avoid confusion with the database software. Continuing pressure from the database server's development community forced another change; on February 9, 2004, Mozilla Firebird became Mozilla Firefox (Firefox for short).
The Firefox project went through many versions before 1.0 was released on November 9, 2004. In addition to stability and security fixes, the Mozilla Foundation released its first major update to Firefox version 1.5 on November 29, 2005. On October 24, 2006, Mozilla released Firefox 2. This version includes updates to the tabbed browsing environment, the extensions manager, the GUI, and the find, search and software update engines; a new session restore feature; inline spell checking; and an anti-phishing feature which was implemented by Google as an extensionand later merged into the program itself.

Security
Firefox uses SSL/TLS to protect communications with web servers using strong cryptography when using the HTTPS protocol. It uses a sandbox security modeland the developers use a "bug bounty" scheme, for finding fixes for some security and feature additions. Official guidelines for handling security vulnerabilities discourage early disclosure of vulnerabilities so as not to give potential attackers an advantage in creating exploits.
ecause Firefox has fewer and less severe publicly known unpatched security vulnerabilities than Internet Explorer (see Comparison of web browsers), improved security is often cited as a reason to switch from Internet Explorer to Firefox.he Washington Post reports that exploit code for critical unpatched security vulnerabilities in Internet Explorer was available for 284 days in 2006. In comparison, exploit code for critical security vulnerabilities in Firefox was available for 9 days before Mozilla shipped a patch to remedy the problem.
2006 Symantec study showed that Firefox had surpassed other browsers in the number of vendor-confirmed vulnerabilities that year through September; these vulnerabilities were patched far more quickly than those found in other browsers.Symantec later clarified their statement, saying that Firefox still had fewer security vulnerabilities than Internet Explorer, as counted by security researchers.As of August 22, 2007, Firefox 2 has six security vulnerabilities unpatched, the most severe of which was rated "less critical" by Secunia.nternet Explorer has ten security vulnerabilities unpatched, the most severe of which was rated "highly critical" by Secunia.

Licensing
Firefox is free and open source software, and is tri-licensed under the Mozilla Public License (MPL), GNU General Public License (GPL), and the GNU Lesser General Public License (LGPL). These licenses permit anyone to view, modify and/or redistribute the source code, and several publicly released applications have been built on it; for example, Netscape, Flock and Songbird make use of code from Firefox.
The official end-user builds of Firefox distributed from mozilla.com are licensed under the Mozilla EULA.everal elements do not fall under the scope of the tri-license and have their use restricted by the EULA, including the trademarked Firefox name and artwork, and the proprietary Talkback crash reporter. Because of this and the clickwrap agreement included in the Windows version, the Free Software Foundation (FSF) consider these builds proprietary software.
In the past, Firefox was licensed solely under the MPL,hich the FSF criticizes for being weak copyleft; the license permits, in limited ways, proprietary derivative works. Additionally, code under the MPL cannot legally be linked with code under the GPL or the LGPL.To address these concerns, Mozilla re-licensed Firefox under the tri-license scheme of MPL, GPL, and LGPL. Since the re-licensing, developers have been free to choose the license under which they will receive the code, to suit their intended use: GPL or LGPL linking and derivative works when one of those licenses is chosen, or MPL use (including the possibility of proprietary derivative works) if they choose the MPL.

rademark and logo issues
The generic globe logo used when Firefox is compiled without the official branding
The name "Mozilla Firefox" is a registered trademark; along with the official Firefox logo, it may only be used under certain terms and conditions. Anyone may redistribute the official binaries in unmodified form and use the Firefox name and branding for such distribution, but restrictions are placed on distributions which modify the underlying source code.
To allow distributions of the code without using the official branding, the Firefox source code contains a "branding switch". This switch allows the code to be compiled without the official logo and name, for example to produce a derivative work unencumbered by restrictions on the Firefox trademark (this is also often used for betas and alphas of future Firefox versions). In the unbranded compilation the trademarked logo and name are replaced with a freely distributable generic globe logo and the name of the release series from which the modified version was derived. The name "Deer Park" is used for derivatives of Firefox 1.5, "Bon Echo" for derivatives of Firefox 2.0, and "Gran Paradiso" is used for derivatives of Firefox 3.0.[citation needed]
Outside of certain exceptions made for "community editions", distributing modified versions of Firefox under the "Firefox" name requires explicit approval from Mozilla for the changes made to the underlying code, and requires the use of all of the official branding. For example, it is not permissible to use the name "Firefox" without also using the official logo. When the Debian project decided to stop using the official Firefox logo in 2006 (because of restrictions on its use incompatible with the project's guidelines), they were told by a representative of the Mozilla Foundation that this was not acceptable, and were asked to either comply with the published trademark guidelines or cease using the "Firefox" name in their distribution. Ultimately, Debian switched to branding their modified version of Firefox "Iceweasel".

Critical reception
Forbes.com called Firefox the best browser in a 2004 commentary piece.PC World named Firefox the "product of the year" in 2005 on their "100 Best Products of 2005" list. After the release of Firefox 2 and Internet Explorer 7 in 2006, PC World reviewed both and declared that Firefox was the better browser. Which? Magazine named Firefox its Best Buy web browser.
Internet Week ran an article in which many readers reported high memory usage in Firefox 1.5. Mozilla developers said the higher memory use of Firefox 1.5 is at least partially an effect of the new fast backwards-and-forwards (FastBack) feature.Other known causes of memory problems are malfunctioning extensions, such as Google Toolbar and some old versions of Adblock, or plug-ins, such as older versions of Adobe Acrobat Reader. When PC Magazine compared memory usage of Firefox, Opera and Internet Explorer, they found that Firefox used approximately as much memory as the other browsers. Tests performed by PC World and Zimbra indicate that Firefox 2 uses less memory than Internet Explorer 7.
Like other browers, Firefox too has had a number of vulnerabilities that have affected its security, although according to CERT, not as many as Internet Explorer.
Softpedia notes that Firefox takes longer to start up than other browsers,which was confirmed by browser speed tests. IE 6 also launches slightly faster than Firefox on Microsoft Windows since many of its components are built into Windows and are loaded during system startup. As a workaround for the issue, a preloader application was created that loads components of Firefox on startup, similar to Internet Explorer.A feature of Windows Vista called SuperFetch does a similar task of preloading Firefox if its usage is high enough.

Relationship with Google
The Mozilla Corporation's relationship with Google has been noted in the media, especially with regards to use of Firefox to provide revenues and data for Google. The release of the anti-phishing protection in Firefox 2 especially raised controversy. Enabled by default, anti-phishing protection is based on a list that is updated about twice per hour and downloaded to the user's computer from Google's server. The user cannot change the data provider within the GUI, and is not informed who the default data provider is. The browser also sends Google's cookie with each request for update.The "advanced" security feature of builds by the Mozilla Foundation activate an anti-phishing feature to provide live protection and, according to the Mozilla Wiki, send each visited URL to Google.The user must explicitly opt-in for this service, however. There are Internet privacy concerns surrounding how Google may use the data, even though Firefox's privacy policy states that Google may not use personal information for any purposes other than the anti-phishing protection feature.
In 2005, the Mozilla Foundation and Mozilla Corporation had a combined revenue of US$52.9 million. Approximately 95 percent of this revenuewas related to their search engine relationships.