I disagree. I would say 'Linux' means writing apps specifically for Linux, using the Linux API etc. I write, amongst other things, web apps that run on Mac OS i

I disagree. I would say 'Linux' means writing apps specifically for Linux, using the Linux API etc. I write, amongst other things, web apps that run on Mac OS in development and Linux in production. I would tick 'web' in this case. Otherwise I would have to click 'Linux', 'Mac' and 'Web'. (I don't disagree that strongly. It's very ambiguous.)