February 17, 2014 11:00 AM The company behind the Oscar-nominated film Dallas Buyers Club in a federal district court in Texas this month for allegedly using the legal file-sharing service BitTorrent to download the movie illegally. The lawsuit is one of thousands that have been brought by companies against BitTorrent users in recent years, in an effort to crack down on Americans who are stealing movies, music, porn, , and. But it could have a tough time. Recently, several federal judges have ruled that key information —computer internet protocol IP addresses—used by film studios and others to target supposed thefts is insufficient proof to proceed with the lawsuits. And copyright experts say that even though companies are still winning lots of settlements, these firms are going after fewer plaintiffs at once than they were a few years ago. This suggests that their ability to pursue large piracy cases has been hampered. This was true in the Dallas Buyers Club case. Instead, they use IP addresses, unique numbers assigned to each device on an internet network, to track the computers that have been used for illegal downloading. Then they ask a judge to issue a subpoena to the internet service providers, so they can obtain the name of the person associated with that IP address. Armed with this information, the plaintiff then typically forces the defendants to settle. Polk Wagner, a law professor at the University of Pennsylvania who specializes in intellectual-property law. The name connected to an IP address usually identifies who is the paying the internet bill, not who is doing the downloading. And all the computers using a single wireless router have the same IP address. So if your tech-savvy neighbor is piggybacking off your wireless internet—and illegally downloading Mean Girls—you could take the heat. The home had an The threats were coming from down the street. Recently, some judges have become more wary about granting subpoenas to companies who come to them with only IP addresses. Last month, a judge in the a case brought by the studio that produced Elf-Man—a direct-to-video Christmas movie—against 152 anonymous defendants. According to the judge, the plaintiff, , relied too heavily on IP addresses and did not do an adequate enough investigation to bring claims. And in May 2012, a federal district judge in New York about IP addresses, as did a the year before. Typically we see no more than 100 defendants…I think that was a smart move on the plaintiffs. For now, whether or not the Dallas Buyers Club producers will be able to successfully subpoena the alleged downloaders remains to be seen. An attorney representing the producers did not return multiple requests for comment. He says movies studios should be able to bring claims that are plausible, based on the facts they gather before suing. But we also saw something incredibly powerful: that truth-tellers don't quit, and that speaking up is contagious. I hope you'll read why, even now, —and why we aren't giving up on our goal of this fall, even though there's a long way to go to get there. Please help close the gap with a tax-deductible donation today. Can you pitch in a few bucks to help fund Mother Jones' investigative journalism? We're a nonprofit so it's tax-deductible , and reader support makes up about two-thirds of our budget. We noticed you have an ad blocker on. Can you pitch in a few bucks to help fund Mother Jones' investigative journalism? THE TRUTH WILL PREVAIL, EVEN NOW. It's been a tough several weeks for those who care about the truth, but we hope you'll read why —and why we need to raise. The erosion of truth we're seeing is downright dangerous, and we're in this fight for the long haul. THE TRUTH WILL PREVAIL, EVEN NOW. It's been a tough several weeks for those who care about the truth. Read why , and please support MoJo with a tax-deductible donation today.