This is probably not news to anyone. But it has been a significant issue in copyright litigation lately. A judge in the of the Northern District of Illinois dismissed a suit filed by the Steele Law Firm on the grounds that it hadn’t identified any individuals as defendants and hadn’t served anyone either. A list of IP addresses would not suffice. Much of the fury over the copyright troll litigation has been that the plaintiffs have a list of IP addresses and nothing more. They then subpoena ISP’s who disclose the name of the subscriber who was assigned the IP address. Plaintiff’s then contact that subscriber demanding money.
This leads to a number of problems, not least of which is that the person who’s name appears on the ISP billing statements is often not the person who did any infringing activities. The infringer, if there is one, might not be in the household or even known to the person being identified. There is often a great deal of pressure to settle however, even if the person identified by the IP address is totally blameless.