This week the first four episodes of 'Game of Thrones' were leaked online. And as the last decade has shown - in movies, TV, music and even books - what was once a trickle of pirated material has turned into a torrent.

HBO's Game of Thrones is notorious for its shock twists, but even the producers couldn't have predicted what happened this week.

With Season 5 of the hugely successful swords-and-sex fantasy about to premiere, the first four episodes were leaked online, with two more reportedly on "private servers". Cue the inevitable firestorm of illegal downloading, streaming and sharing, across legitimate and dodgy websites both.

Ironically, the new season was seen as the jewel in HBO's launch of their US streaming service, HBO Now (the show airs on Sky Atlantic over here, one day after broadcast Stateside). It demonstrated once more the, ahem, double-edged sword that is digital technology, though none was needed.

Leaks of TV shows, movies, music, even books - not to mention classified documents, as per Bradley Manning et al - is virtually its own "black economy" industry by now. Game of Thrones is the most-pirated show ever; Jeff Bewkes of Time Warner (which owns HBO) once welcomed it, describing bit-torrents and illegal streaming as "better than an Emmy" for promotion.

To list every leak of the last 10 years would require more storage than a GoT box-set, but we can mention some high-profile ones. In TV, an uncensored version of South Park episode 201 was leaked in 2014; this is notable because it had been pulled due to death threats from Islamic extremists.

Last winter the infamous hack of Sony Picture's hard-drives saw a clutter of upcoming films released into the wild: Fury, Annie, Mr Turner and Oscar-winner Still Alice among them. Weirdly, the North Korean dictatorship was originally blamed, as a threat to Sony not to release their Kim Jong Un-baiting comedy The Interview.

More embarrassingly, personal emails were also posted online. Angelina Jolie was called "a minimally talented, spoiled brat" by one executive, and Sony's tech people literally use words like "Password" as passwords.

As for music, the Web has made the notion of copyright little more than a quaint anachronism. Lady Gaga, Coldplay, Madonna and Kanye West are just some of the many - all, really - artists pirated in the past decade.

U2 have suffered more than most. As far back as 1997, a Hungarian fan ripped a promo copy of Pop and uploaded it. In 2004 another album was copied after a CD was left in a taxi. Most bizarrely, No Line on the Horizon was pinched when a Dutchman walked past Bono's French mansion, heard the new music blasting inside and recorded it on his mobile. (Then they gave away the last one for free and got pilloried for it - you can't win.)

Even scripts aren't immune. A few years ago, a man was arrested for stealing one of the final Breaking Bad screenplays from Bryan Cranston's car. Other scripts stolen include Terminator: Salvation, The Avengers, Prometheus and - rather hilariously - The Fifth Estate, a drama about Wikileaks guru Julian Assange.

Books are another unlikely target for hacking, but in 2007 some demented obsessive photographed all 54,000 (roughly) pages of the final Harry Potter and uploaded them. In an odd twist, JK Rowling was later revealed to be behind the Robert Galbraith pseudonym, when the friend of the wife of one of her legal firm's partners - stay with us - leaked it on Twitter.

Stephenie Meyer suffered the same fate in 2008 when 12 chapters of her Twilight spin-off Midnight Sun were leaked. And Roy Keane's latest autobiography was leaked, except this was in real life, not online: a Manchester Tesco's accidentally put it on sale three days too early.

How damaging are these leaks, in practical terms? Buzzfeed journalist and pop culture aficionado Declan Cashin says: "Some areas of entertainment are more vulnerable than others. I'd argue it can be more damaging to movie studios - it's hard enough to get people to trek to cinemas. With TV, I'm not sure it's very damaging at all.

"I saw legal previews of Game of Thrones last week, and still watched it on TV this week. And with the TV landscape so packed in a time-poor age, many shows are happy their product is getting any buzz. It seems mutually beneficial, for now anyway."

Is there anything to be done about it? Probably not. Producers use every trick in the book - watermarks on previews, private screenings/listening booths, encoded CDs, locked iPods in locked rooms, threats, prosecution…nothing works. The digital Pandora's Box is open now: once something can be converted to 1s and 0s, there's no physical way of controlling it.

Netflix's system of (usually) releasing entire shows at once to subscribers, thus pulling the rug from under the pirates, seems to offer a solution. But even that isn't immune to calamity: earlier this year they accidentally let loose the entire third season of House of Cards a month ahead of schedule.

Entertainment journalist Michael Doherty, of the RTE Guide, reckons it's "practically impossible to stop leaks nowadays. Take movie press screenings: even though they're held as close to the release date as possible, and usually accompanied by men in black standing in the wings with infrared cameras - I kid you not - no film has a 100pc guarantee of not being pirated."

There is, in all of this, the sneaking suspicion that sometimes a leak is not alone welcomed, but purposely done. Declan says, "I have no doubt some leaks are deliberate. It makes good sense to control a 'leak' to generate hype."

Michael concurs: "It feels that way. Die-hard fans are going to buy the album or see the movie anyway, so it's a nifty way to drum up interest among casual consumers and the media."

One way or the other, leaks are woven into the fabric of modern life and culture, and won't be untangled any time soon. And maybe they're not such a new thing anyway.

The script of Citizen Kane was leaked to newspaper magnate William Randolph Hearst in the 1940s; critic Pauline Kael later speculated that this led to the cancellation of a Radio City Hall premiere, and thus hobbled the film's commercial prospects, and thus began the slow demise of Orson Welles.

They can also be a force for good. Back in 1772, one Benjamin Franklin leaked a packet of letters written by the royal governor of Massachusetts, who said discontented colonists could be subdued "by depriving them of their liberties". Ben's piratical deed fired up the Yankees' rebellious spirit and eventually led to American independence - an act of political sophistication and ruthlessness worthy of any Game of Thrones contender.