It is the same with programmers who writes open source programs just for fun of it. And I remember in 2000x there were people who thought that it is a bad idea. There were even lawsuits filled by programmers who couldn't sell their programs because they were left without customers due to open source solutions.
Or the whole Wikipedia thing, that at first was dismissed by traditional publishers, whom then were bankrupted and buried by an army of free working amateurs.
