Caution is spreading among popular file-sharing services known for letting users circulate pirated Hollywood content.
FileSonic, FileServe and Uploaded.to have abruptly cut off the sharing of movies, games and other software just days after the Justice Department closed down Megaupload, the largest such site.
"It looks like the chilling effect has already started," says Dennis Fisher, editor in chief of security blog Threatpost. "Maybe one of the reasons the U.S. government is going after companies alleged to be hosting infringing content is to serve as a deterrent for others engaging in similar activity."
FBI and Department of Justice officials do not discuss ongoing investigations.
File-sharing services, also referred to as cyberlockers, enable users to easily upload, store and share large files on a server in the Internet cloud. This includes movies, music, gaming applications, software tools, multimedia presentations and the like.
But cyberlocker companies have not come up with a good way to consistently stop copyright infringement. "As soon as you let users trade files back and forth, you really don't have much control," says Wade Williamson, senior security analyst at firewall supplier Palo Alto Networks.
The motion-picture industry, for one, has been pushing U.S. regulators to enforce copyrights with respect to film content showing up in cyberlockers.
One recent measure of how widespread the problem is comes from Palo Alto Network's recent analysis of the Internet traffic at 1,636 companies, with more than 4 million employees, in the second half of 2011.
The analysis found employees at six in 10 companies used Megaupload to download large content files. Overall, 25 percent of corporate traffic to and from cyberlockers came from Megaupload, which specialized in entertainment content. Some 22 percent came from Dropbox, a workplace productivity and collaboration service, followed by 15 percent from MediaFire, another entertainment-oriented service. The next three most-active cyberlockers in corporate settings were entertainment-oriented: FileSonic, 4shared and FilesTube.
FileSonic is noteworthy because it has recently begun to establish formal distribution agreements with artists. Those contracts could be frozen if the authorities were to pursue copyright-infringement actions against FileSonic.
FileSonic couldn't be reached for comment.
"They appear to be able to deliver files in an above-board way," says Williamson. "In shutting down the ability of their users to trade files back and forth, they may be moving to protect their flank."
FileSonic, based in the U.K., posted a message on its website: "All sharing functionality on FileSonic is now disabled. Our service can only be used to upload and retrieve files that you have uploaded personally."
Last December, FileSonic began scanning user uploads in an effort to stop copyrighted material from going on the site.
Meanwhile, Derek Labian, co-founder and CEO of Shenandoah, Texas-based MediaFire, says what's happened with Megaupload is "concerning" but won't stop MediaFire from continuing business as usual. MediaFire has 25 million account users.
"We're a U.S.-based company and follow U.S. law. It's pretty much that simple for us," says Labian. FileSonic's move to disable certain downloads is "pretty drastic," he says.
It is troubling that legitimate digital storage services should feel compelled to monitor their users, says intellectual property director Corynne McSherry of the San Francisco-based Electronic Frontier Foundation. "In terms of privacy, that should be a concern," she says.
Explore further: Megaupload: a boon to users but a bane for copyright holders