I like the snow shovel analogy, since it's easy to understand but allows for discussion of many of the nuances and tradeoffs: http://www.econlib.org/library/Co

I like the snow shovel analogy, since it's easy to understand but allows for discussion of many of the nuances and tradeoffs: http://www.econlib.org/library/Columns/Mcchesneysnow.html http://www.econlib.org/library/Columns/Mcchesneysnow.html When it snows hard in Chicago, people have to shovel out parking spaces for their cars. But no one will want to do this if someone else can just take the space as soon as they leave. So the rule (not a law, but socially enforced) is that the person who shovels the space "owns" it for a limited time. This means that people can do useful work and be rewarded for it. But their "property" returns to the public after the snow melts. (Think about how the outcomes would change if the "ownership" were just for one day, or if it were forever.) This doesn't capture all the interesting things about copyright (like the non-scarcity and zero marginal cost of information goods) but it does capture some important differences between "intellectual property" and real property that get left out of most discussions. And the Chicago parking system is controversial just like many copyright issues.