Richard Roeper has a lengthy complaint about unattributed internet copying in his Hollywood Urban Legends (yes, it's relevant to his discussion!), because, yes, people apparently take things from the internet all the time without attribution. Even news organizations.

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Gillian

"Now everyone was giving her that kind of look UFOlogists get when they suddenly say, 'Hey, if you shade your eyes you can see it is just a flock of geese after all.'"

"You can't erase icing."

"I can't believe it doesn't work! I found it on the internet, man!"