It is rather disappointing that github heads down the Mac OS path while they base their company around a concept which is rather strange to most things Apple - openness and sharing. Writing for Mac OS first also makes it harder to port to other platforms as it is a rather idiosyncratic platform.

If they insist on pushing Mac OS AND want to be seen as a good free software citizen they might want to consider putting some effort in the GNUstep project. Once GNUstep is up to par they should be able to build for that on Linux and Windows with minimal porting efforts.

Still, I'm disappointed in the lack of vision many of these so-called 'open source' companies exhibit. Don't they realise that by pushing these closed, proprietary platforms they undermine the very base of their own existence? The software and community which github depends on was not the result of the generous sponsorship from Microsoft and Apple after all...