Comedian Ari Shaffir performs at the 2015 Bonnaroo Music and Arts Festival in June in Manchester, Tenn. Shaffir has said fellow comedian Carlos Mencia stole his joke about who would build a fence on the U.S.-Mexican border. Copyright on jokes is difficult to prove, and it turned out two other comedians had made similar jokes as well. John Davisson/Invision/AP hide caption

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Author Joyce Carol Oates, seen here at a a panel discussion last October, sparked jokes, and then a debate, by tweeting about the "barbaric" killing of a triceratops. Thos Robinson/Getty Images for The New Yorker hide caption

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President Barack Obama might have just gotten his own Twitter account, but he's been tweeting for years, such as during this "Twitter Town Hall" in 2011. Charles Dharapak/AP hide caption

itoggle caption Charles Dharapak/AP

The Two-Way

President Gets His Own Twitter Account: 'It's Barack. Really'

Obama's bio on @POTUS says he is "Dad, husband and 44th President of the United States."

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Twitter changed its direct messaging guidelines Monday. Now, any user can direct-message any other user even if they are not following each other. The new feature is not automatically enabled; users will have to opt in. iStockphoto hide caption

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Purdue University students are testing new software that may track and warn about tornadoes, such as this one which struck Rochelle, Ill., in early April. Walker Ashley/AP hide caption

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Some colleges and police departments are starting to use software that scans social media to identify local threats, but most tips still come from members of the public. Ikon Images/Getty Images hide caption

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Friday, DeMarcus Cousins of the Sacramento Kings reminded sports journalist Clay Travis that his five-year guarantee — that Cousins would be arrested — had expired. Thearon W. Henderson/Getty Images hide caption

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Panelist Nahshon Ellerbe, a star running back at Trinity Christian Academy in Addison, Texas, warms up before a game against Midland Christian. Jeffrey McWhorter/Trinity Christian Academy hide caption

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Social media provides voice to movements and helps drive them. Picking the right platforms for these sensitive conversations, though, is a sign of our growing digital sophistication. iStockphoto hide caption

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