Open Source Software in comon use

Open source software is realy the only truly free software out there.
We all use them everyday without ever even knowing or thinking about it.

WordPress -         most popular blogging sofware (220 million )
Firefox -               second most used web browser
Apache -             most widely used web server
MySql -                most widely used database (used by google)
Oscommerce -      Popular ecommerce platform
Zencart -              Out of box eccommerce website
VLC Player -       multimedia cross platform player
Filezilla -             ftp client and server
Audacity -           music production suite (popular in europe)
VNC -                   remote access software (most commercial products are based on it. Teamviewer, showmypc etc.)
OpenOffice -      only real rival to microsoft office (microsoft now train sales rep how to counteract openoffice)