Twitter has started taking down jokes for copyright infringement. The removals were first spotted by @PlagiarismBad, which traced the takedown notices to Olga Lexell, a freelance writer in Los Angeles.

Lexell, whose bio describes her as a freelance writer, confirmed that she had asked Twitter to take down jokes. In her post, Lexell says she makes her living writing jokes, and that the users who had tweeted them — many of them spam accounts that "re-post tons of other people's jokes every day" — did not give her credit.

But Lexell may not have a good copyright claim, according to Jim Burger, a Washington, D.C.-based copyright attorney.

"You can copyright a joke, but it's not a very strong copyright," he says. "And a lot of jokes are derivative of other jokes, so I think you would have a hard time defending your copyright."

Christopher Jon Sprigman, a law professor at New York University who has written about jokes and copyright, agrees. He says you can't copyright an idea, only a way of expression; if a joke can only be expressed in a few ways you probably can't get a copyright on it.

Among Lexell's reposted jokes that were taken down by Twitter: "Saw someone spill their high-end juice cleanse all over the sidewalk and now I know God is on my side."

Sprigman says it's debatable whether that joke can be copyrighted. Sometimes, he says, a joke is just in the zeitgeist of the moment.

Take the case of Carlos Mencia, who made a joke during an appearance on Comedy Central about plans to build a fence along the southern U.S. border to keep Mexicans from entering the U.S. illegally. Mencia quipped, "Um, who's going to build it?"

Comedian Ari Shaffir claimed Mencia stole the joke from him, and cited earlier recordings of himself making the joke — but it turned out that comedians D.L. Hughley and George Lopez also had told similar jokes.

Sprigman says that, historically, the comedy community has policed itself by shaming those who steal jokes.

Copyright 2016 NPR. To see more, visit