io9 has put together this chart showing how six large corporations essentially control the pop culture franchises that make up our common experience.
The chart doesn't really represent ownership as much as it represents control. New Line Cinema doesn't own The Lord of the Rings, only the film version. And Harper Collins doesn't own Tolkien's novels, only the publishing rights. But when you see how much these six companies control, it's clear why copyright and digital rights management have become major issues and why the United States is leaning heavily on other countries, including Canada, to write legislation to protect U.S. corporate assets.
The chart is also incomplete. Notice that while Disney is listed, none of the drawn animated characters are on this chart. Neither is Nickelodeon or CBS (both Viacom companies), though Cartoon Network makes it. That just shows that what's here is only the tip of the iceberg. The odds are that if you've bought a book, seen a movie, bought a DVD or watched TV, you've been feeding these corporate behemoths.