Thanks for explaining these concepts so simply and eloquently. I have never thought of BSD and GPL in that fashion, now I do. The penny has dropped for me.
IINAL either.
I think the essential concept that people need to understand is that there are consistent intellectual property laws in all westernized nations. These cover trademarks, patents and copyrights.
http://strategis.ic.gc.ca/sc_mrksv/cipo/cp/copy_gd_protect-e.html
By releasing your work under an "open source license" like GPL, BSD or the creative commons, you can share your information more openly. By allowing other people to participate you will create something greater than you could have created on your own.
I recommend Michel Bawen's P2Pfoundation wiki which provides a good overview of how using the "open source idea" empowers people in areas other than software development.
P2P Intellectual Property Concepts
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