Firefox is the most popular web browser in the Linux world and the most used. Its strength and its reliability is legendary and its capabilities cover every need in terms of navigation, safety, utility, beauty and usability. This is not the place to describe all the potential of this wonderful instrument, but just think to hundreds of additional software that makes Firefox a complete tool for your Internet experience.

Firefox Plug-ins
Adblock plug-in (blocks ads on web pages)
Adblock Plus block ads that appear on web pages. You can subscribe to a free filtering service and apply ads with a single click.
sudo apt-get install mozilla-firefox-adblock
You can add this extension from Firefox → Tools → Add-ons → Get Add-ons → Browse All Add-ons. (This method also provides automatic updates)
Noscript plug-in (check scripts)
Noscript plugin is one of the most important measures for the security in Internet surfing. Most viruses and trojans from your computer gain access to the Internet through scripts. This plugin lets you choose which scripts can run and which ones can't.
sudo apt-get install mozilla-noscript
You can add this extension from Firefox → Tools → Add-ons → Get Add-ons → Browse All Add-ons. (This method also provides automatic updates)
User Agent Switcher plug-in for Firefox
User Agent Switcher plugin allows the web browser to masquerade as another web browser, allowing content suited for specific browsers, to be shown.
You can add this extension from Firefox → Tools → Add-ons → Get Add-ons → Browse All Add-ons. (This method also provides automatic updates)
Video Download Helper plug-in for Firefox
The plugin Video Download Helper lets you download video (including Flash movies) from websites like YouTube.
You can add this extension from Firefox → Tools → Add-ons → Get Add-ons → Browse All Add-ons. (This method also provides automatic updates)
Unplug Download Management
The add-on UnPlug lets you save video and audio embedded within web pages.
You can add this extension from Firefox → Tools → Add-ons → Get Add-ons → Browse All Add-ons. (This method also provides automatic updates)
Adobe Acrobat Reader plug-in for Firefox
This plugin is available from the Medibuntu repository. Allows you to view Adobe Acrobat files within Firefox.
Adobe Flash Player Plug-in for Firefox
To install official Adobe Flash plugin (Flash 10) for Firefox:
sudo apt-get install adobe-flashplugin
Gnash Plug-ins (Flash Player Open Source Substitution)
Gnash is available in a 64-bit version as well as a 32-bit.
sudo apt-get install gnash
After installation, change the preferences of your browser so that SWF files and SPL is used Gnash.
VLC plug-in for Firefox
This package allows you to play the popular VLC media player in Firefox.
sudo apt-get install mozilla-plugin-vlc
Gecko MediaPlayer Plug-in for Firefox
Gecko MediaPlayer is a browser plugin for all Gecko-based browsers (Firefox, SeaMonkey, iceape, Opera) that allows MPlayer to play multimedia in the browser. Install:
sudo apt-get install gecko-mediaplayer
An alternative is to use the mplayer plugin for Firefox. Install:
sudo apt-get install mozilla-mplayer
Kaffeine Plug-in for Firefox
This package allows the Kaffeine media player (often used in desktop based on KDE) to play multimedia in Firefox.
sudo apt-get install kaffeine-mozilla
Helix player plug-in for Firefox
This package installs the Helix player (open source player that plays Real Player content on Linux) as well as the plugin that plays RealMedia within Firefox.
sudo apt-get install mozilla-helix-player
FireFTP for Firefox
FireFTP is a Firefox extension for FTP transfers.