What is Open Source?

Please watch the short movie. It will show some aspects of Open source software.

Open Source definition

"Open source software is defined by its attached license guaranteeing anybody rights to freely use, modify, and redistribute the software."

Ken Coar (Vice president of The Open Source Initiative) states that Open source doesn't just mean access to the source code. The distribution terms of open-source software must comply with more criteria like 'License Must Not Restrict Other Software' (if you want you can optionally read them).

If you want to learn more about it: please visit the webist of http://www.opensource.org/

Open vs closed / for free vs commercial

Carlo van Haren, a well-known open source specialist shows us in the next table what open source means. So it doesn't equal free of charge! On the other hand even applications with closed sources can be free of charge. 

Of course the names of the products are just examples and the list can be much longer but it gives you an idea.