Free / Open Source Software (FOSS) have a long way from the works started by the father of the Free Software foundation, Richard M. Stallman to the produce of the open source community and Linux.
But basically, the reason for its success is the freedom given back to the community. The freedom to study, use, modify, and redistribute the software empowered the community to be sustainable and capable of producing the best software applications in the world.
Linux, Apache, OpenOffice.org, Moodle, Sugar CRM, Blender, Joomla, PHP, MySQL, Perl, Ruby, etc. are some examples. The advantages of the open source model of development showing great potential and superior performance against that of the proprietary counterpart as shown by Eric Raymond in the "Cathedral and the Bazaar".
These freedom when quantified resulted to the attainment of highest possible level of systems efficiency in organization by greatly reducing software licensing and development cost as we have observed and tested here at the ICT Division of the Office of the Vice President of the Republic of the Philippines under the Honorable Vice President Noli "Kabayan" de Castro, the CICT Office of the President of the Republic of the Philippines and as published in the different ePrimers of the International Open Source Development Network (IOSN).
FOSS therefore is by far offers a more cost-effective and efficient long-term solution for any group or organization.