conversion; in these cases, a plaintiff must choose which claim to make based on what amount of damages they seek to recover. In the electronic age The common law tort of trespass to chattels has been invoked in the modern context of electronic communications to combat the proliferation of unsolicited bulk email, commonly known as spam. In addition, several companies have successfully used the tort to block certain people, usually competitors, from accessing their servers. Though courts initially endorsed a broad application of this legal theory in the electronic context, more recently other jurists have narrowed its scope. As trespass to chattels is extended further to computer networks, some fear that plaintiffs are using this cause of action to quash fair competition and to deter the exercise of free speech; consequently, critics call for the limitation of the tort to instances where the plaintiff can demonstrate actual damages. Rules The trespass to chattels tort punishes anyone who substantially interferes with the use of another's personal property, or chattels. Plaintiffs must show that the offender had intentional physical contact with the chattel and that the contact caused some substantial interference or damage. The courts that imported this common law doctrine into the digital world reasoned that electrical signals traveling across networks and through proprietary servers may constitute the contact necessary to support a trespass claim. Applying this common law action to computer networks, plaintiffs must first prove that they received some type of electronic communication (typically bulk e-mail or spam) that the defendant intentionally sent to interfere with the plaintiff's interest in his or her property and second that this communication caused a quantifiable harm to their tangible property, such as impaired functioning of the computer, network or server. Early applications of trespass to chattels to computer networks In the late 1990s, when the World Wide Web was in its infancy, courts were more receptive to extending the trespass to chattels tort to the electronic context. In CompuServe Inc. v. Cyber Promotions, Inc., a 1997 case that was the first to extend the trespass theory to computer networks, a federal district court held that a marketing company's mass mailing of a high volume of unsolicited advertisement emails to CompuServe subscribers constituted an actionable trespass to chattels. CompuServe customers repeatedly received unwanted advertisements from Cyber Promotions, a company that specialized in sending marketing email in bulk. Cyber Promotions also modified its equipment