Jimmy Wales, creator of online giant Wikipedia, launched a petition on Sunday against the extradition to the United States of a British student accused of copyright infringement.
The founder of the free Internet encyclopedia said Richard O'Dwyer, a 23-year-old student at Sheffield Hallam University in northern England, had become caught in a war being fought by "content providers" and Internet users.
British Home Secretary Theresa May approved the deportation of O'Dwyer, who created a website allowing people to watch films and television shows for free, in March.
Wales launched the petition on the Guardian newspaper's website, and accused the "moguls of Hollywood" of using their muscle to bring about "endless encroachments on our civil liberties."
O'Dwyer allegedly earned tens of thousands of pounds (dollars) through advertising on the TVShack website before it was closed down by US authorities.
Wales said the student "struck me as a clean-cut, geeky kid" when they had met and "precisely the kind of person one can imagine launching the next big thing on the Internet."
"Given the thin case against him, it is an outrage that he is being extradited to the US to face felony charges," he wrote in the Guardian.
The entertainment industry has been fighting a running battle with websites over their illegal use of copyrighted material.
"O'Dwyer is the human face of that battle, and if he's extradited and convicted, he will bear the human cost," warned Wales.
A spokeswoman for the Home Office, Britain's interior ministry, said the government had found "no statutory bars to his surrender" when approving his extradition.
"On March 9 the Home Secretary, having carefully considered all relevant matters, signed an order for Richard O'Dwyer's extradition to the US," she said.
O'Dwyer's mother Julia said her son was being "sold down the river" by the British government.
"If Richard appears to have committed a crime in this country, then try him in this country," she said.
The student would be the first British citizen extradited for such an offence. He faces jail if found guilty of the charges, which were brought after a crackdown by the US Immigration and Customs Enforcement agency.
His lawyer had argued in court that the website did not store copyright material itself and merely directed users to other sites, making it similar to Google.
The lawyer also argued that his client was being used as a "guinea pig" for copyright law in the United States.
The court heard that after O'Dwyer was arrested in London in November 2010, he admitted to police that he owned TVShack.net and TVShack.cc and earned about Â£15,000 (18,000 euros, $23,500) a month from online advertising.