

HBO Go is a popular product available on tablet computers, regular computers and even some television media extension boxes. It offers every episode of many popular series, including “Game of Thrones,” as well as many movies that can be seen in a Netflix-like on-demand way.

But the only rub? It’s only available for HBO subscribers, and it’s nearly impossible to find HBO’s programming anywhere else. So when the cable channel has a popular show like “Game of Thrones,” it’s no wonder it has become the most-pirated show of the year. For the second time.

Torrenfreak, which tracks illegal downloads of many television shows and movies, said just a single episode of “Game of Thrones” in 2012 was downloaded 4.28 million times, although the site did not share which episode was the most-pirated. The most viewed episode of the entire series was the recent Season 2 finale, which drew 4.2 million viewers, meaning that illegal downloads for that one particular episode trumped all the legal viewers.

Although Napster and its music sharing was popular more than a decade ago, to transfer television shows and movies, a form of peer-to-peer transfer called bit-torrent is the most popular. Studios have tried to combat the illegal transfers that take place online, which has helped boost products like Netflix Streaming, Hulu and others. But HBO has always stayed out of other people’s products, and even had public battles with companies like Netflix, making it clear it was not interested in including its programming on the popular service.

With that, it leaves a lot of non-subscribers of HBO in the dark for its shows, and many of them turn to illegal download services.

And some believe that because there are no commercials, they are not stealing. But they are. HBO’s original programming is used to help boost subscribers, so it’s the influx of subscribers that, in part, fund shows like “Game of Thrones.” While the number of viewers for a show is important, what premium cable channels like HBO look for is how it affects the subscriber base.

If some people feel they can just download episodes of HBO’s shows illegally, they won’t ever be persuaded to purchase a subscription to HBO, and that’s lost revenue for the cable channel which could easily affect the fate of a show.

Many fans have publicly berated HBO for not making its programming more available, and that’s why so many people pirate it. However, it does not seem availability makes too much of an impact in terms of numbers. The second-most-pirated series was Showtime’s “Dexter,” with 3.85 million downloads for a single episode. Right behind it are two popular network shows that are available at no cost in many urban areas — “Big Bang Theory” and “How I Met Your Mother” on CBS, both with around 3 million downloads for a single episode.

Behind them was the popular AMC series “Breaking Bad,” which had just under 2.6 million downloads for a single episode.

“Game of Thrones” returns for its third season in March on HBO.