The other day I criticized the GNU GPL for capitulating to the fundamental model of so-called intellectual property -- i.e., insisting that the creator must assert control (enforced through government) over who may or may not propagate the creator's work. While I contribute all of my personal creations directly into the public domain, all of the protocol specifications I write for the Jabber Software Foundation are licensed under the Creative Commons Attribution License. Plus, I work for a company that releases code only under commercial licenses (though they generously support open standards). Doesn't that make me a hypocrite?
Perhaps. I'm not morally opposed to copyright, I think shareware and payware are fine things, and I'm not about to make a religious issue out of putting code and text into the public domain (I haven't gotten religious about anything since I gave up my youthful Randianism). So while I think there is little reason to be afraid of the public domain, I don't cast aspersions at those who still fear it. These issues are complex, and I don't claim to have definitive answers for all creative people and for all time.
Yet I do think there are plenty of ways to make money (though perhaps not plenty of money) even if you place your creative products in the public domain. Penguin Classics make money by selling books whose text is in the public domain. Theatre companies make money by performing Shakespeare. Folk singers make money by playing folk songs, as do musicians who play Bach, Beethoven, and the boys. These companies and individuals offer products (books and CDs) and experiences (concerts and plays) that have value even if the underlying "code" is free as the air.