The idea is that which you make available under GPL (NOT giving away your copyright) can then be modified or improved by others who can pass it back to you as of right. Commensurate with that, is that you cannot rip someone else's GPL code to create your own product without them having dibs to your additions: after all, you wouldn't have got as far as you have without their efforts.

The real cost of reproducing software is essentially zero. The real cost of hardware is of course never zero.

If anyone wants my source code drivers for various things, I see no harm in releasing them under GPL. Its just that I always feel faintly embarrassed by the quality of my own code.

Steve