Knight had argued that Viacom could not claim that he was violating its copyright when the video contained material which he had originated.
YouTube removed the video from the site pending an investigation, but has now reinstated the file.
"In accordance with the Digital Millennium Copyright Act, we have completed processing your counter-notification regarding your video," the YouTube statement said. "This content has been restored and your account will not be penalised."
Knight gave thanks to Fred von Lohmann, a senior staff attorney at the Electronic Frontier Foundation, for his help.
"There is no telling how much grief and headache Fred [von Lohmann] and his crew have prevented, not just for me but for a lot of other people too," Knight wrote on his Knight Shift blog.
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