YouTube's history and search history are separate tabs that users may want to use to clear their past usage, as seen in this screen grab. NPR hide caption

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A man reads a copy of the satirical newspaper La Bougie du Sapeur (The Sapper's Candle), published every leap day, in a Parisian cafe on Feb. 29, 2008. The paper's tagline is "without reproach." Patrick Hertzog/AFP/Getty Images hide caption

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An image from a superPAC ad attacking Newt Gingrich, whose campaign called on TV stations to pull the ad off the air. Restore Our Future hide caption

itoggle caption Restore Our Future

The publisher of the Philadelphia Inquirer and the Philadelphia Daily News has been accused of interfering with coverage of the newspapers' pending sale. Joseph Kaczmarek/AP hide caption

itoggle caption Joseph Kaczmarek/AP

Supporters of the website The Pirate Bay, one of the world's top illegal file-sharing websites, demonstrate in Stockholm, Sweden, in 2009. Fredrik Persson/AFP/Getty Images hide caption

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An Egyptian stock trader reads a copy of the Al-Masry Al-Youm newspaper last November. Critics say the newspaper is reluctant to criticize the ruling military council and has engaged in self-censorship. Amr Nabil/AP hide caption

itoggle caption Amr Nabil/AP