eBay, Inc. (defendant) was an online marketplace for new and used goods. Individuals listed goods for sale to others, and eBay received money from both listings and actual sales. Because fraud was easily perpetrated through sales on eBay, eBay implemented several measures to reduce fraud, including employing thousands of employees to fight fraud, using computer programs to detect fraud, and suspending sellers and transactions that involved counterfeit goods. Tiffany (NJ) Inc. and Tiffany and Company (Tiffany) (plaintiffs) manufactured and sold high-end jewelry. Second-hand Tiffany goods were sold on eBay, many of which were counterfeit. Whenever Tiffany notified Ebay of a potentially fraudulent listing, eBay promptly removed the listing. Despite this, Tiffany sued eBay for, among other things, contributory trademark infringement. After a bench trial, the district court ruled for eBay on the contributory-infringement claim. Tiffany appealed.