An innovative and highly praised open source Web browser for Windows, Mac and Linux from the Mozilla project. Including a search box for Google and other major sites, the Firefox user interface was designed to be easily customizable by adding extensions

Introduced in 2004, Firefox received rave reviews and caused much notoriety. Within a few months, millions downloaded it, and by mid-2005, Firefox captured more than 10% of the Web browser market, a huge gain in such a short time. By 2008, it reached 18%. Many view it as a safer alternative to Microsoft's Internet Explorer (IE) browser, which is constantly being attacked.

Whether Firefox is safer because it was designed better than IE or simply because very few hackers have a quarrel with open source software, is an ongoing debate.