CompuServe v. Cyber Promotions
In the Internet context, trespass to chattels first appears in cases by ISPs against spammers.
In CompuServe v. Cyber Promotions, for example, Cyber Promotions sent massive amounts of unsolicited commercial email to the clients of the ISP, CompuServe. The volume of email imposed a significant burden on CompuServe’s computers; CompuServe’s clients complained about the unsolicited email in their inboxes, and some of them cancelled their accounts with CompuServe.
CompuServe sued for trespass to chattels. (“Chattel” is an old word for personal property; the personal property in this case is CompuServe’s computers.)