To me, it's not a problem that my code is used for commercial gain. I use the MIT licence (a permissive licence). The key thing for me is that it doesn't give companies a competitive advantage, rather it puts companies that don't use it at a competitive disadvantage. It's thanks to Open Source that I'm writing this on a system that uses 100% Open Source software (okay, maybe the BIOS isn't). A good thing about Open Source is that if a company uses it, they're more likely to report / fix bugs, which helps everyone.

Same here, though I usually use the AGPL for extra freedom.