the GPL licence is a very open and unselfish model where future developers have the chance to use the code developed by any individual or company. this is why the source code publishing is important. If a company does not agree with this they should not use the previous developed code and start from scratch. So for the layman you can use anybody work under GPL as long as you put back your work into the community pot by publishing your source code. this is a very innovative model allowing companies or individual to come with quick solutions and MAKE A PROFIT for as long as they contribute back. Withholding your source code is like stealing the code and putting your name on it and not wanting to share further. GPL license should be enforced drastically by not complying is stealing not from a company or individual but from a whole community. Jcase is right retailer profiting from GPL infringement is as guilty as the developer.