No. My understanding (from the document) is as such: If you have a software package that you are *distributing*, you must release all GPL source code that went into building the binary. In most cases, specifically noncommercial, you can simply say 'I used gcc, linux 2.6.21, readline, etc. unmodified'. The source is available from their respective websites, and if you were a 'good citizen' you would mirror that source code yourself. Now, what about your 'proprietary' software that you wrote? From what I gather on this document, the following is true: 1. Did you modify the source code of any GPL software? If yes, simply publish the modified source along side with your application, or provide a notice saying that it is available upon request. 2. Are you using GPL software 'as intended'? Linux is intended to 'launch software', etc. GCC is intended to 'compile sources', etc. If you can reasonably say you are 'using the software as intended', you are fine. It is my understanding that the GPL does not care about what 'other software' you are using on your system. The GPL only cares about GPL software. The hard part is determining exactly when your own software inherits the GPL license - and this is defined by the legal term 'Derivative Work'. PS: crap how do I do line breaks?