open source + Linux, why adopt it as a alternative to commercial software?

strengths of the operating system:

networking + server apps apache
security
robustness
economy in costs

strengths of open-source:

permits the sharing of information through access to a community of users and projects
http://freshmeat.net
http://sourceforge.net
makes development of custom applications easier and faster through the sharing of the source code
promotes the emergence of standards and interoperability between programs