A reader writes, "Creative Commons has published an extensive interview with Lewis Hyde, author of the modern classic 'The Gift: Creativity and the Artist in the Modern World' and a brand new, deeply historical book on the cultural commons, 'Common as Air: Revolution, Art, and Ownership'."
It is surely the case that the GPL has antecedents in gift cultures. As I explain in The Gift, one old ethic asks that gifts be "kept in motion"; they ought to be passed along in the same spirit with which they were received. Put another way, in a gift culture one is not supposed to capitalize on the generosity of others or of the community.
That said, such ethics belong to custom rather than law; the wit of the GPL was to give legal footing to the gift ethic of the software community. As for antecedents in that line, I note in Common as Air that I found one other example of a gift norm that got grounded in law: Pete Seeger and his friends secured the copyright on "We Shall Overcome," then set up a trusteeship to donate the money earned to support "African-American music in the South." That trusteeship has a "claim and release" structure not unlike the one built into the later GPL.
As for links between the Creative Commons license suite and my sense of copyduty, I'm not sure these need be limited to the "Share Alike" option. Many are the duties that arise from a person's sense of both self and community. One might, for example, feel a duty to contribute to the public domain with no strings attached, in which case "copyduty" would be best expressed by the CC0 tool. That was Benjamin Franklin preferred mode, by the way. He believed that any claim to own his ideas and inventions could only lead to the kind of disputes that "sour one's Temper and disturb one's Quiet." He never took a patent or registered a copyright.
Lewis Hyde, author of Common as Air: Revolution, Art, and Ownership