Technology makes it easy to lift parts of someone else's music, video or other digital creations, tweak it, and call the result one's own. This usually causes no harm, but the case of a photo-turned-poster of Barack Obama is a reminder that just because technology makes something possible doesn't make it right.

Until the digital age, the common view of copyright law was that it served overreaching corporations against creative little guys. Groucho Marx once generated publicity for the Marx Brothers film "A Night in Casablanca"...