IT departments should worry about the careless and improper use of peer-to-peer (P2P) networks, as the problem of leaked business data by unsuspecting users is getting worse. The recent data breaches at Pfizer (personal data of 17,000 employees) and ABN Amro Mortgage Group (personal data on 5,000 customers), both due to careless use of file-sharing programs, are two high-profile examples, but many more undoubtedly exist. According to the Center for Digital Strategies at Dartmouth College, file sharing is an increasing security threat to businesses, and steps should be taken to minimize their risk. Used as intended, of course, P2P networks and file-sharing programs are an easy, inexpensive, and convenient way for people to share content. The problem is that far too often, people unknowingly save a sensitive business file in the same folder they share personal files, and then both have the potential to be exposed. IT departments should, first and foremost, set rules for the use of file-sharing applications on company PCs. Some departments have banned the use of file-sharing applications altogether, but if that step is not taken, IT departments should use tools to manage and monitor the rules that have been put in place. A number of products exist to help in this regard, including products from Cisco, Audible Magic, Cymphonix, and FaceTime. Watching for data leaks is another important step, although it is time consuming and has the big challenge of limited visibility. One company, Tiversa, has developed proprietary algorithms that, in real time, monitor P2P networks and give a comprehensive view of file-sharing activity. The Dartmouth College researches suggest that businesses should educate everyone about the dangers of P2P sharing, create home-use policies, and use file-naming conventions that are less likely to be spread.