I wrote enough patches to ZFSOnLinux that I have the distinction of number 2 by commit count. It was a hobby for me at first and quite frankly, I never expected it to make a difference for more than a few hundred people. Now ZoL is on millions of systems through Ubuntu in part because of my work and there are far more places using it than I can count.<p>Open sourcing those patches rather than keeping them to myself made a difference that was greater than anything I imagined. Similarly, the impact of making ZFS open source far surpassed the expectations of the original team at Sun. I think that making any worthwhile piece of software open source will lead to adoption beyond the scope of what its authors envisioned. All it takes is people looking for something better than what previously existed.<p>As for closed source being inherently evil (your words, not mine), how do you fix bugs in closed source software that a vendor is not willing to fix? How do you catch things like a hard coded password that gives root privileges? How do you know that the software is really as good as they say? It is far easier with open source software than with closed source software. Closed source software is a bad idea.