Copyright trolling is the business model of monetizing copyright infringement claims at scale — typically by filing mass lawsuits against anonymous “John Doe” internet users and extracting settlements priced below the cost of defense. Matthew Sag wrote the foundational empirical scholarship documenting this phenomenon, and federal courts across the country — including the Seventh Circuit — have cited it in confronting the practice.
The empirical work
Copyright Trolling, An Empirical Study, 100 Iowa Law Review 1105 (2015), documented the rise of multi-defendant John Doe litigation in the United States district courts, showing that this form of litigation had grown to a remarkable share of the federal copyright docket and that it was strongly associated with claims relating to pornographic films — features that distinguish opportunistic monetization from ordinary copyright enforcement. The underlying data are public on this site’s data sets page.
Defense Against the Dark Arts of Copyright Trolling, 103 Iowa Law Review 571 (2018) (with Jake Haskell), turned the diagnosis into a playbook: a doctrinal and practical guide to the weaknesses in the trolls’ cases — on IP-address evidence, joinder, discovery, and damages — for defendants and courts.
The wider empirical context appears in IP Litigation in US District Courts: 1994 to 2014, 101 Iowa Law Review 1065 (2016), Empirical Studies of Copyright Litigation (Edward Elgar Research Handbook, 2019), and — on remedies — Discovering eBay’s Impact on Copyright Injunctions Through Empirical Evidence, 64 William & Mary Law Review 1447 (2023) (with Pamela Samuelson).
In the courts
This scholarship has been cited in dozens of federal court decisions. The article’s definition of a copyright troll — a plaintiff “more focused on the business of litigation than on selling a product or service,” playing “a numbers game” of settlements “priced just low enough that it is less expensive for the defendant to pay the troll rather than defend the claim” — has become the standard judicial formulation, quoted from Malibu Media, LLC v. Doe, 2015 WL 4092417 (S.D.N.Y. 2015) onward. Notable citations include:
- Design Basics, LLC v. Lexington Homes, Inc., 858 F.3d 1093 (7th Cir. 2017) — the Seventh Circuit citing the trolling scholarship in an architectural-copyright troll case;
- Strike 3 Holdings, LLC v. Doe, 351 F. Supp. 3d 160 (D.D.C. 2018) — Judge Lamberth quoting Defense Against the Dark Arts on the trolls’ strategy: “file a deluge of complaints; ask the court to compel disclosure of the account holders; settle as many claims as possible; abandon the rest”;
- a long line of Malibu Media and Strike 3 John Doe decisions in district courts across the country (S.D.N.Y., E.D. Cal., N.D. Ill., D.N.J., S.D. Tex., W.D. Wash., and others) relying on the articles’ definitions and filing statistics;
- GS Holistic decisions (D. Colo. 2023) importing the “paradigmatic troll” framework into trademark law — the taxonomy migrating across IP regimes.
Key publications
- Copyright Trolling, An Empirical Study, 100 Iowa Law Review 1105 (2015)
- Defense Against the Dark Arts of Copyright Trolling, 103 Iowa Law Review 571 (2018) (with Jake Haskell)
- IP Litigation in US District Courts: 1994 to 2014, 101 Iowa Law Review 1065 (2016)
- Twelve Year-Olds, Grandmothers, and Other Good Targets for File Sharing Litigation, 4 Northwestern Journal of Technology & Intellectual Property 133 (2006) — an early analysis of mass end-user enforcement