Twenty-five years ago today, a young, little-known programmer by the name of Bram Cohen fired off a short message<\/a> to a mailing list for peer-to-peer enthusiasts. \u201cMy new app, BitTorrent, is now in working order, check it out here,\u201d Cohen wrote, followed by a link to his personal website.<\/p>\n<\/div>\n \u201cWhat\u2019s BitTorrent, Bram?\u201d the founder of the list asked in response.<\/p>\n<\/div>\n Cohen never bothered to reply. The world would find out soon enough.<\/p>\n<\/div>\n In the following years, BitTorrent quickly became the world\u2019s most popular file-sharing app, unleashing a massive wave of piracy that upended Hollywood forever. At one point, BitTorrent was said to be responsible for a huge amount of internet traffic \u2014 some<\/a> widely<\/a> cited<\/a> metrics<\/a> peg it at half of P2P and one-third of all internet traffic in 2004. And while the entertainment industry succeeded in shutting down file-sharing systems like Napster and Kazaa, it largely failed to curtail the massive flood of BitTorrent piracy.<\/p>\n<\/div>\n What stymied movie studios and record labels alike is exactly what makes the story of BitTorrent\u2019s 25th anniversary a gripping one. There\u2019s BitTorrent, the app that Cohen unveiled in July 2001 and which continues to attract tens of millions of monthly users to this day. There\u2019s BitTorrent, the file-sharing protocol, which has been adopted and advanced by hackers and developers from around the world, and which helped birth an entire cottage industry of piracy websites. And there\u2019s BitTorrent, the company cofounded by Cohen, which struggled for years to make money with its technology.<\/p>\n<\/div>\n \u201cGoing into it, my plan was not to start a business,\u201d Cohen recalls. \u201cMy plan was to start a revolution.\u201d<\/p>\n<\/div>\n This is the story of that revolution, and all that remains of it today.<\/p>\n<\/div>\n Cohen started working on BitTorrent soon after leaving Mojo Nation, a startup that had ambitious plans to combine file sharing, distributed computing, and micropayments, only to shut down in 2002 without ever really getting off the ground.<\/p>\n<\/div>\n Cohen helped Mojo Nation improve the efficiency of its file-sharing technology. His approach was to use something called swarming distribution: Instead of swapping large files between a few users at a time, the app would divide each file into lots of little chunks, and then allow large numbers (or swarms) of users to trade those chunks among themselves. The ethos of sharing was built into the software, insisting that users would help upload files instead of just downloading them selfishly.<\/p>\n<\/div>\n Cohen was disillusioned by the failure of Mojo Nation but not ready to give up on the underlying technology just yet. \u201cI decided to make a tool that very narrowly just did swarming distribution and nothing else, because that was a thing I knew how to do,\u201d he says.<\/p>\n<\/div>\n \u201cMy plan was not to start a business. My plan was to start a revolution.\u201d<\/p>\n<\/div>\n<\/div>\n All this happened as P2P and file-sharing companies were facing massive headwinds. The music industry sued Napster<\/a> at the end of 1999 and ultimately forced it to shut down<\/a> around the time Cohen first released BitTorrent. A few months after that, the entertainment industry sued Kazaa and Grokster<\/a>, followed by legal claims against Audiogalaxy<\/a>, LimeWire<\/a>, eDonkey<\/a>, and other file-sharing systems.<\/p>\n<\/div>\n Despite some significant differences in their P2P architecture, all these apps ultimately lost in court or folded ahead of a likely legal defeat. Their Achilles\u2019 heel: They offered users a way to search for copyrighted files and then helped them find others to trade those files with. Courts deemed this contributory infringement, pointing to the fact that the owners of these services knew exactly which files their users were trading.<\/p>\n<\/div>\n BitTorrent was different. From the start, Cohen built the app without search functionality, instead relying on third-party websites for content discovery. He also didn\u2019t run a centralized server to help users discover other BitTorrent clients to trade content with, and instead outsourced that piece of the puzzle to so-called tracker servers. Websites dedicated to BitTorrent file sharing would offer a metadata file (the torrent file) for every download, which in turn pointed users to tracker servers that matched up users to facilitate the sharing. Simply put, BitTorrent was an app to help people trade data, but its developer had no way of knowing what that data was.<\/p>\n<\/div>\n That structure effectively shielded Cohen and the company he would eventually found from legal liability. To this day, BitTorrent remains the only major publisher of file-sharing software that hasn\u2019t gotten sued by Hollywood and the major labels. However, Cohen insists that the decision to outsource content search and client discovery wasn\u2019t primarily a shrewd legal maneuver, but a simple necessity.<\/p>\n<\/div>\n After all, he was just one guy. \u201cMy hands were somewhat tied,\u201d he says. \u201cI was writing stuff on my own.\u201d<\/p>\n<\/div>\n Despite lacking the resources of much bigger P2P companies, Cohen\u2019s BitTorrent app quickly gained traction in tight-knit communities looking to trade large files. Among the first adopters was Etree, an online community of jam band enthusiasts. Bands like Phish and the Grateful Dead had long encouraged their fans to trade bootleg recordings of their shows with each other in the offline world. Etree brought this idea online with the help of BitTorrent, which allowed fans to share show recordings using high-resolution audio files that were simply too big to distribute any other way.<\/p>\n<\/div>\n But pirated videos were like rocket fuel. \u201cWhen it started getting used for anime was when the numbers took off,\u201d Cohen says. Granted, that early success didn\u2019t quite measure up to the tens of millions of users apps like Kazaa were attracting at the time. \u201cIt was like, Oh, look, we\u2019re getting a thousand downloads a day, that\u2019s massive<\/em>,\u201d he recalls.<\/p>\n<\/div>\n Things changed significantly with the emergence of major torrent sites, which allowed anyone to quickly find and download movies and TV shows. In 2002, a Slovenian high school student launched Suprnova.org<\/a>, which reportedly attracted<\/a> up to a million users a day before its closure in 2004. And in 2003, a ragtag group of hackers founded The Pirate Bay in Sweden. With its open embrace of illicit content and an F-you attitude toward Hollywood, the site turned into a kind of lightning rod for self-described pirates and copyright enforcers alike.<\/p>\n<\/div>\n \u201cIt was so fast that we initially thought something was broken.\u201d<\/p>\n<\/div>\n<\/div>\n While these sites quickly became household names, countless others sprung up all across the globe in their shadows. Some catered to specific interests like anime, porn, or \u201970s B movies, while others simply welcomed everyone and everything. And while copyright holders were able to shutter some sites, others survived, or reemerged under different names or domains. Plus, all those lawsuits generated countless headlines, effectively promoting BitTorrent to new audiences. By 2004, BitTorrent traffic exploded.<\/p>\n<\/div>\n The surge of interest didn\u2019t just alarm rightsholders. It also put some significant strain on BitTorrent\u2019s infrastructure, including the tracker servers that helped users discover each other. One popular tracker, Denis.Stalker.H3Q.com, was run by a trio of German hackers associated with the local Chaos Computer Club.<\/p>\n<\/div>\n Initially, their tracker ran server software Cohen had written in conjunction with the BitTorrent client app. But as BitTorrent gained in popularity, their server, which was just a single computer humming along in a kitchen somewhere in Berlin, was bombarded with hundreds of requests per second, slowing it to a crawl.<\/p>\n<\/div>\n That\u2019s when Dirk Engling, a member of the trio who is also known as Erdgeist in German hacker circles, decided to build a better-performing tracker software from scratch. He dubbed his server software Opentracker, and the difference was like night and day: While the Denis.Stalker server previously always ran hot, Engling\u2019s code put a sudden stop to the near-constant fan noise. \u201cIt was so fast that we initially thought something was broken,\u201d he says.<\/p>\n<\/div>\n Engling is not as well known as Cohen. But back then, he made a fateful decision that ultimately helped BitTorrent scale to surpass all other file-sharing networks in popularity. Instead of just using his code on the Denis.Stalker tracker, Engling published it online<\/a>, free to download for anyone.<\/p>\n<\/div>\n Opentracker quickly took off and was adopted by major torrent sites like The Pirate Bay as their tracker solution of choice. Many of these big sites relied on third-party tracker servers like Denis.Stalker, but for years also ran their own trackers as fallback solutions. Every torrent file can point to multiple tracker servers, so sharing continued when one server went down. (Eventually, BitTorrent added further decentralization to allow trackerless trading, but tracker servers remain to this day an important part of the ecosystem.)<\/p>\n<\/div>\n \u201cBack then, it was a radical political idea,\u201d Engling says. The thought was to allow anyone to distribute large amounts of data without having to rely on expensive servers \u2014 and if some of that was used for piracy, so be it. \u201cIt was a movement to democratize [file sharing],\u201d he says.<\/p>\n<\/div>\n Engling, for one, wasn\u2019t in it for the money. He distributed Opentracker as \u201cbeerware,\u201d an open-source license guided by the notion that anyone who found it useful should buy him a beer, as he half-jokingly explained in a 2007 talk<\/a>. \u201cI thought: A lot of people are using BitTorrent, so\u2026\u201d<\/p>\n<\/div>\n Back in the United States, Cohen quickly realized that relying on the goodwill of others \u2014 especially people who used his software to download content for free \u2014 didn\u2019t pay the bills. In 2004, he founded BitTorrent Inc. to transform the revolution he had started into an actual business. \u201cThat didn\u2019t work so well, unfortunately,\u201d he now concedes.<\/p>\n<\/div>\n BitTorrent raised $8.75 million in funding in 2005, followed by another $20 million round in 2006. The money helped the company to staff up, but it also put pressure on Cohen and his teammates to somehow turn an app that was beloved by pirates into a legitimate business.<\/p>\n<\/div>\n As part of these efforts, the company struck deals with Hollywood to launch a movie download store called the BitTorrent Entertainment Network, which launched with thousands of titles from Warner Bros., Paramount, and MGM in early 2007. However, the company quickly realized that selling DRM-protected movies to an audience that already had access to the same titles for free was a fool\u2019s errand.<\/p>\n<\/div>\n \u201cBack then, it was a radical political idea.\u201d<\/p>\n<\/div>\n<\/div>\n \u201cThat didn\u2019t work at all,\u201d says a former senior BitTorrent employee who declined to be named in this story because of fear of repercussions from his current employer. Not only did people not want to buy movies from BitTorrent, but minimum guarantee provisions in its contracts with Hollywood also forced the company to fork over millions of dollars for content no one wanted to buy. \u201cIt kind of worked out for the studios,\u201d the former employee says.<\/p>\n<\/div>\n \u201cThere were gotchas [in those] deals that made them essentially unworkable,\u201d Cohen agrees. \u201cThe big copyright holders were perfectly happy with where things [were], and basically didn\u2019t want to create the streaming systems that we have today.\u201d<\/p>\n<\/div>\n BitTorrent closed the download store less than two years after its launch while also laying off half of its staff<\/a> amid a recapitalization. In the years that followed, the company kept trying to figure out other business models, from P2P CDNs to decentralized chat clients \u2014 only to hit roadblocks at every turn.<\/p>\n<\/div>\n The big issue was always piracy. BitTorrent successfully avoided legal liability, but it couldn\u2019t get rid of its outlaw image. That made it impossible to strike deals that were open to others, Cohen says. \u201cWhen you\u2019re doing slightly sketchy things, the world doesn\u2019t want to give you a nice off-ramp.\u201d<\/p>\n<\/div>\n \u201cI never should have brought on anybody else at all. I could have simply gotten enough money off of doing the slightly sketchy stuff just on my own.\u201d<\/p>\n<\/div>\n<\/div>\n One thing that worked was advertising. In addition to including ads directly in its products, BitTorrent would also bundle third-party tools with its installers and get a small cut when someone installed a browser toolbar or a similar app alongside the BitTorrent client. But while the ad money was paying the bills, it wasn\u2019t meeting the expectations of BitTorrent\u2019s investors looking for a lucrative exit.<\/p>\n<\/div>\n \u201cThe [app download] numbers kept growing, but a lot of the use cases were never going to be the kind that you could legitimately either IPO or sell to another company,\u201d the former employee says.<\/p>\n<\/div>\n BitTorrent Inc.\u2019s struggles were in stark contrast to the success of Cohen\u2019s technology. \u201cWe were moving an exabyte of data every month,\u201d the former senior employee estimates. BitTorrent owed much of its popularity to the wars around file sharing, which got a new poster child when Swedish authorities raided<\/a> The Pirate Bay in 2006.<\/p>\n<\/div>\n The battle between rightsholders and The Pirate Bay is perhaps the best-known part of the BitTorrent saga. The site was up and running again days after the raid, thanks in part to BitTorrent\u2019s distributed architecture. The Pirate Bay didn\u2019t run a file-sharing network, and taking its servers didn\u2019t stop people from downloading BitTorrent\u2019s client, or finding each other via tracker servers. All the raid took offline was a public list of downloadable torrent files, and all it took to get that back online was a recent server backup.<\/p>\n<\/div>\n Undeterred, rightsholders and law enforcement continued their crusade against BitTorrent pirates and their alleged enablers, including the three cofounders of The Pirate Bay. After getting charged with criminal copyright infringement in early 2008, in April 2009 they were each sentenced to a one-year prison term and ordered to pay financial damages. Much to Hollywood\u2019s chagrin, their site nonetheless stayed online. The exact identity of The Pirate Bay\u2019s new operators remains a mystery to this day.<\/p>\n<\/div>\n Hollywood\u2019s fight against pirates also had repercussions for the German hackers responsible for much of BitTorrent\u2019s tracker infrastructure. Used by a number of big torrent sites, the Denis.Stalker tracker attracted around 100 million daily peers at its peak, which were trading a million files every single day, according to Engling.<\/p>\n<\/div>\n \u201cWhen you\u2019re doing slightly sketchy things, the world doesn\u2019t want to give you a nice off-ramp.\u201d<\/p>\n<\/div>\n<\/div>\n One day, the Berlin police\u2019s economic crimes unit raided the apartment of one of the three people involved in running the tracker server, confiscating every piece of equipment they could find, according to Engling. \u201cThey couldn\u2019t imagine that anyone was running something like this without making any money with it,\u201d he says. However, money was the last thing on the trio\u2019s mind. In the same aforementioned talk, held during the Chaos Computer Club\u2019s annual conference between Christmas and New Year\u2019s, they explained their motivation with three simple words: \u201cBecause we can.\u201d<\/p>\n<\/div>\n Charging them for knowingly facilitating copyright infringement wasn\u2019t possible either, as tracker servers simply match users by hash values and never see the actual files being traded. Ultimately, the case was dismissed, according to Engling.<\/p>\n<\/div>\n \u201cThose were the wild early days,\u201d he says.<\/p>\n<\/div>\n Things changed rapidly in subsequent years. Unable to put an end to torrent sites and trackers, rightsholders shifted their focus to end users. In some jurisdictions, including Germany, this can be extremely lucrative. Law offices can effectively send cease and desist letters that double as invoices for hundreds of euros per traded file to alleged offenders, threatening them with full-blown lawsuits if they don\u2019t pay up. Germany\u2019s Stern<\/em> magazine estimated<\/a> that local file sharers received claims for around \u20ac120 million in 2010 alone.<\/p>\n<\/div>\n That led to end users embracing VPNs to protect themselves \u2014 and torrent sites cashing in on that trend by adding ads for privacy services to their sites. With that, torrent sites were starting to become a major moneymaker. One 2014 study estimated<\/a> that torrent sites generated around $114 million in ad revenue that year. In addition to VPNs, torrent sites have long been hawking anything from porn to dating to online casinos, with the occasional malware download thrown in for good measure.<\/p>\n<\/div>\n These days, some sites also use elaborate schemes to hijack otherwise legitimate advertising and affiliate revenues. One such trick: When someone uses a torrent site, their browser opens an Amazon page for an extremely random product in the background. Toothpaste, maybe, or perhaps a totally unremarkable sweater. The goal isn\u2019t to sell those specific products, but to plant a cookie on the visitor\u2019s machine. If they order anything from Amazon in the following 24 hours, the pirates earn some affiliate revenue \u2014 a tactic known as cookie stuffing<\/a>.<\/p>\n<\/div>\n \u201cIt\u2019s whatever the latest scam is,\u201d says Engling, sounding disillusioned about what has become of the BitTorrent world he helped create. \u201cThe idea of democratization got lost,\u201d he says.<\/p>\n<\/div>\n But while Torrent sites were making bank, BitTorrent Inc. continued to struggle. \u201cI did a good enough job of keeping the wheels from falling off the bus, keeping our core product working,\u201d Cohen says. Efforts to move beyond file sharing, however, kept failing.<\/p>\n<\/div>\n That included Cohen\u2019s next big bet: For years, he worked on adapting the company\u2019s tech for low-latency livestreaming. BitTorrent Live, as the initiative was called, even shipped consumer apps, and the company was briefly working on building a kind of live online TV service. In 2017, the company pulled the plug on those efforts<\/a> and laid off almost the entire BitTorrent Live team. \u201cThis is part of the world being out to get you,\u201d Cohen says, clearly still bitter that the project wasn\u2019t given a chance. \u201cThat was a product that worked great and was ready to go, and was just outright fucking killed.\u201d<\/p>\n<\/div>\n \u201cThey couldn\u2019t imagine that anyone was running something like this without making any money with it.\u201d<\/p>\n<\/div>\n<\/div>\n Soon after, BitTorrent Inc. got sold<\/a> to controversial crypto entrepreneur Justin Sun, who went on to shutter the company\u2019s SF office<\/a> after a few very tumultuous years<\/a> and now operates the company from overseas. (BitTorrent did not respond to multiple requests for comment.) \u201cIt eventually got an even sketchier exit than it had been all along,\u201d Cohen quips.<\/p>\n<\/div>\n Looking back, Cohen believes that many of BitTorrent\u2019s troubles could have been avoided if he hadn\u2019t gone down the typical path of a VC-backed startup. Perhaps he should have just done his own thing \u2014 not unlike the path Engling chose, except more focused on modest revenue and less on free beer.<\/p>\n<\/div>\n \u201cI never should have brought on anybody else at all,\u201d Cohen says. \u201cI could have simply gotten enough money off of doing the slightly sketchy stuff just on my own.\u201d<\/p>\n<\/div>\n How many people still use BitTorrent today is unknown. The days of it making up a third of all internet traffic are clearly over, with one estimate suggesting<\/a> that it now contributes less to residential upstream traffic than iCloud and FaceTime. BitTorrent Inc., the company cofounded by Cohen and now owned by Sun, claims that its clients still have 54 million monthly users<\/a>. Popular third-party clients like Transmission, BiglyBT, and qBittorrent likely attract millions more.<\/p>\n<\/div>\n