Yes: writing open source for companies. Much fewer do it as a hobby, and those can't sustain large projects.

When I do something is just the outcome of dabbling in something as part of learn process, just contributing back some bug reports or minor fixes.

Hence why I tend to pay for the software I use, either via donations, buying author's books, distribution CD/DVDs, or actually buying licenses.

I believe that the authors from the tools I earn money with, should also get a piece of the cake.