Folks, simmer. I believe what he meant was that, sometimes, simply being 'open source' implies being able to view the source code.. even if the license if harmfully limited and prevents you from actually USING it (depending on your situation). On the other hand, if you mean Open Source (as in the Open Source Initiative (OSI) standards) then you're generally open to use the source code as long as you provide attribution, source code, etc.