Moglen: How Should the Free Software Movement View the Linux Foundation?

The reason why people contribute back to FreeBSD because to choose FreeBSD, you've had to make a conscious decision to do so. Chances are when that happens, is that the people are BSD contributors already.

OTOH Linux gets lots of GPL violations because people get a vendor BSP with Linux and have no clue about GPL. And down the stream, coercing the GPL sources for the kernels after violations *does* happen. Sure, these kernels are unsuitable for contributing back to upstream kernel, but people have used them to build their own kernels for devices. For example the scene of custom kernels for android phones. And that's the important part of copyleft - to allow people to change things - the goal isn't to force vendors to contribute back upstream.

AOSP vs kernel is good example. All the big-name vendors give GPL sources for their phones, but few release their changes of the non-copyleft AOSP.