The popularity of using peer-to-peer to share and download copyrighted MP3s is well known, but research indicates downloading TV episodes also is popular.
Research company Big Champagne revealed Heroes was the most popular illegal TV download in 2009, with 55 million people downloading episodes. In the No. 2 spot was Lost, racking up downloads from 51 million users.
This "casual piracy" is helping to replace regular viewing hours traditionally spent watching content in the living room on TV.
"Millions of television viewers now access free, unauthorized versions of favorite shows at least some of the time," according to Eric Garland, Big Champagne CEO, who spoke with BBC. "This is a socially acceptable form of casual piracy - and it is replacing viewing hours."
All shows in the top 10, as noted by Big Champagne, were American reality shows and other popular TV series. Around 47% of the downloads originated from the United States, with only 4% coming from the UK.
Copyright holders are concerned P2P users will be interested in sharing unauthorized copies of TV episodes, in a shift away from copyrighted music files.
TV studios are working with Internet broadcasters and cable providers, as there is more on-demand services and online sites that show full-length TV episodes. To help counter online piracy, episodes are often available either through a third-party site like Hulu, or on the official broadcaster's web site.
The most popular movie torrents cited in the study were Watchmen, The Curious Case of Benjamin Button, and Yes Man -- with 16M, 13M and 13M downloads, respectively.
