Copyright vs Copyleft: Life Without Microsoft

I enjoyed Adam's lecture this morning about open source software as opposed to proprietary software. I hadn't ever heard of Gnu/Linux much less used it but I definitely like the sound of it. Primer confused me but I found the rehashing of the time travel parody surprisingly interesting. Especially after Adam's lecture spouting the glories of Gnu/Linux: as much as we resent and criticise Microsoft and its proprietary software regime, one has to wonder if it was the advent of these very programs which provided the catalyst for a more basic/user-friendly open source program such as Gnu/Linux. Any thoughts out there? Anywhere? Anyone?