Megaupload, Filesonic, Fileserve Has Been Seized !

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 Williams, 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% of corporate traffic to and from cyberlockers came from Megaupload, which specialized in entertainment content. Some 22% came from Dropbox, a workplace productivity and collaboration service, followed by 15% from MediaFire, another entertainment-oriented service. The next three most-active cyberlockers in corporate settings were entertainment oriented: FileSonic, 4shared and FilesTube.