Patent troll is a pejorative term used for a person or company that enforces its patents against one or more alleged infringers in a manner considered unduly aggressive or opportunistic, often with no intention to manufacture or market the product. A related, less pejorative expression is non-practicing entity (NPE) which describes a patent owner who does not manufacture or use the patented invention.
Etymology and definition 
The term "patent troll" was used as early as 1993 to describe companies that file aggressive patent lawsuits. The Patent Troll was originally depicted in "The Patents Video" which was released in 1994 and sold to corporations, universities and governmental entities. In "The Patents Video", an unsuspecting victim is surprised by the Patent Troll who strategically positions himself to collect patent licensing revenue.
The metaphor was popularized in 2001 by Peter Detkin, former assistant general counsel of Intel, who chose the term from amongst a number of suggestions during a discussion with Anne Gundelfinger, Vice President and Associate General Counsel at Intel. Detkin first used it to describe TechSearch, its CEO, Anthony O. Brown, and their lawyer, Raymond Niro, while Intel was defending a patent suit against them. Detkin had previously used the term "patent extortionist" to refer to a number of companies who were suing Intel for patent infringement and who were trying to "make a lot of money off a patent that they are not practising and have no intention of practising and in most cases never practiced." After Intel was sued for libel, he began using the term "patent troll" instead. Those accused of being patent trolls typically viewed Intel as being a large and manipulative company who had stolen their ideas.
By 2005, Detkin believed that the term was being used to mean any unpopular plaintiff, a more broad definition than he had originally intended. Some definitions could be applied to Intel themselves, contrary to Detkin's intention, in view of their routine practice of asserting patents that they had bought but were not practising.
Patent troll is currently a controversial term, susceptible to numerous definitions, none of which are considered satisfactory from the perspective of understanding how patent trolls should be treated in law. Definitions include a party that does one or more of the following:
- Purchases a patent, often from a bankrupt firm, and then sues another company by claiming that one of its products infringes on the purchased patent;
- Enforces patents against purported infringers without itself intending to manufacture the patented product or supply the patented service;
- Enforces patents but has no manufacturing or research base;
- Focuses its efforts solely on enforcing patent rights; or
- Asserts patent infringement claims against non-copiers or against a large industry that is composed of non-copiers.
The term "patent pirate" has been used to describe both patent trolling and acts of patent infringement. Related expressions are "non-practising entity" (NPE) (defined as "a patent owner who does not manufacture or use the patented invention, but rather than abandoning the right to exclude, an NPE seeks to enforce its right through the negotiation of licenses and litigation"), "patent assertion entity" (PAE), "non-manufacturing patentee", "patent shark", "patent marketer", "patent assertion company", "patent licensing company", and "patent dealer".
Patent trolls may buy patents cheaply from entities not actively seeking to enforce them. For example, a company may purchase hundreds of patents from a technology company forced by bankruptcy to auction its patents.
The cost of defending against a patent infringement suit, as of 2004, is typically $1 million or more before trial, and $2.5 million for a complete defense, even if successful. Because the costs and risks are high, defendants may settle even non-meritorious suits they consider frivolous for several hundred thousand dollars. The uncertainty and unpredictability of the outcome of jury trials also encourages settlement.
If the patent office accepts claims that have been invented, published or even patented before, ignoring material prior art, then even existing technologies in use are subject to patent trolling. Reexamination to invalidate the patent based on prior art can be requested, but requests are typically made only after a lawsuit is filed or threatened (About 0.33% of patents in U.S. have reexam requested but this number also reflects the low percentage of issued patents for which re-examination is requested.) and often in conjunction with an infringement lawsuit. Only the patent holder will participate in this process, and the party requesting the reexamination has no right of appeal and is estopped from using the same evidence in any subsequent civil action; this risk keeps the popularity of reexamination low despite its lower cost.[self-published source?] Furthermore, the most common outcome is not the validation or invalidation of the patent, but narrowing the scope of the claims.
There is also no obligation to defend an unused patent immediately, thus manufacturing companies may produce the patented product for years until the patent troll sues them. For example, the JPEG format, intended to be free of license fees, was subject to two patent attacks, one by Forgent Networks during 2002–2006 and another by Global Patent Holdings during 2007–2009. Both patents were eventually invalidated based on prior art, but before this, Forgent collected more than $100 million in license fees from 30 companies and sued 31 other companies (see JPEG#Patent issues and references therein).
In 2011 patent trolls cost US bodies direct costs totalling 29 billion dollars in the United States alone. A core criticism of patent trolls is that "they are in a position to negotiate licensing fees that are grossly out of alignment with their contribution to the alleged infringer's product or service", notwithstanding their non-practising status or the possible weakness of their patent claims. The risk of paying high prices for after-the-fact licensing of patents they were not aware of, and the costs for extra vigilance for competing patents that might have been issued, in turn increases the costs and risks of manufacturing.
On the other hand, the ability to buy, sell and license patents is seen by some as generally productive. The Wall Street Journal argued that by creating a secondary market for patents, these activities make the ownership of patents more liquid, thereby creating incentives to innovate and patent. Patent Licencing Entities also argue that aggregating patents in the hands of specialized licensing companies facilitates access to technology by more efficiently organizing ownership of patent rights.
In an interview conducted in 2011, former U.S. federal judge Paul R. Michel regarded "the 'problem' [of non-practising entities, the so-called "patent trolls"] to be greatly exaggerated." Although there are a number of problems with the U.S. patent system, i.e. "most NPE infringement suits are frivolous because the defendant plainly does not infringe or the patent is invalid", "patent infringement suits are very slow and expensive", and venue abuses, "[...] NPEs may add value to the patents by buying them up when manufacturers decline to do so. Inventors may have benefited from the developing market in patent acquisition."
Patent trolls operate much like any other company that is protecting and aggressively exploiting a patent portfolio. However, their focus is on obtaining additional money from existing uses, not from seeking out new applications for the technology. They monitor the market for possibly infringing technologies by watching popular products, news coverage and analysis. They also review published patent applications for signs that another company is developing infringing technology, possibly unaware of their own patents. They then develop a plan for how to proceed. They may start by suing a particularly vulnerable company that has much to lose, or little money to defend itself, hoping that an early victory or settlement will establish a precedent to encourage other peer companies to acquiesce to licenses. Alternately they may attack an entire industry at once, hoping to overwhelm it.
An individual case often begins with a perfunctory infringement complaint, or even a mere threat of suit, which is often enough to encourage settlement for the nuisance or "threat value" of the suit by purchasing a license to the patent. In the United States, suits are often brought in United States District Court for the Eastern District of Texas, known for favoring plaintiffs and for expertise in patent suits.
The uncertainty and unpredictability of the outcome of jury trials also encourages settlement. If it wins, the plaintiff is entitled as damages an award of at least a "reasonable" royalty determined according to the norms of the field of the patented invention.
Patent trolls are at a disadvantage in at least two ways. First, patent owners who make and sell their invention are entitled to awards of lost profits. However, patent trolls, being non-manufacturers, typically do not qualify. Further, patent owners' rights to bar infringers from manufacture, use, or sale of technologies that infringe their patents has recently been curtailed in the 2006 court decision eBay v. MercExchange. Rather than automatically granting an injunction, the US Supreme Court stated that Courts must apply a standard reasonableness test to determine if an injunction is warranted. Writing in Forbes about the impact of this case on patent trolls, writer Jessica Holzer concludes: "The high court's decision deals a blow to patent trolls, which are notorious for using the threat of permanent injunction to extort hefty fees in licensing negotiations as well as huge settlements from companies they have accused of infringing. Often, those settlements can be far greater than the value of the infringing technology: Recall the $612.5 million that Canada's Research in Motion forked over to patent-holding company NTP, Inc., to avoid the shutting down of its popular BlackBerry service." 
The non-manufacturing status of a patent troll has a strategic advantage, in that the target infringer cannot counter-sue for infringement. In litigation between businesses who make, use or sell patented technology, the defendant will often use its own patent portfolio as a basis to file a counterclaim for infringement. The counterclaim becomes an incentive for settlement, and in many industries, discourages patent infringement suits. Additionally, a patent suit carries with it the threat of an injunction or mutual injunction, which could shut down manufacturing or other business operations. If a patent owner does not make, use or sell technology, the possibility of a counter-suit for infringement would not exist. For this reason a patent troll is able to enforce patents against large companies which have substantial patent portfolios of their own. Furthermore, patent trolls may use shell companies.
Benefits from patent trolls 
Many small inventors[vague] have difficulty benefiting from their inventions. For example, sometimes the inventors are not able to commercialize their products and they cannot afford defending their patents. Then selling the patent to a patent troll may be a way to benefit from the invention, thus encouraging innovation and promoting science and technology. An alleged patent troll chief says that the companies are just leveling the playing field between big companies and inventors and small patent holders, who previously "were getting their rights steamrolled by big companies." This market for "small patents" in some cases poorly serves inventors who sell their patents expecting continuing royalties only to find that the purchasing company isn't producing any profit that is subject to royalties and is actively destroying any potential for small inventors to profit from their inventions.  The costs and benefits caused by patent trolls have also been documented in a study by Boston University.
Defenses against patent trolls 
Patent troll "companies have no interest in using the patents... but instead hope to reap large sums of money from the lawsuits themselves." This gives them an advantage over manufacturers since they are relatively immune to the typical defensive tactic large entities use against small patent plaintiffs, because the cost of litigation tends to fall more heavily on an accused infringer than on a plaintiff with a contingency-fee lawyer, and because trolls have an almost-unrestricted ability to choose their preferred plaintiff-friendly forums, most prominently the Eastern District of Texas.
Many common techniques used by companies to protect themselves from producing competitors are rendered ineffective against patent trolls. These techniques include monitoring patent activities of competitors to avoid infringing patents (since patent trolls are not competitors, productive companies usually have no way to find out about the troll or its patents until after significant investments have been made to produce and market a product); going on the offensive with counterclaims that accuse the patent plaintiff of infringing patents owned by the defendant (the mutual threat often leads the parties to arrive at a mutually beneficial cross-licensing arrangement); or a "scorched earth" defense designed to drive up litigation costs (which is equally ineffective because patent trolls plan for and have the finances to fully litigate a case; in fact, some are able to draw on hedge funds and institutional investors to finance their patent cases). Patent "pooling" arrangements where many companies collaborate to bring their patented knowledge together to create new products are also inapplicable to patent trolls because they don't produce products.
Substantial companies that attempt over-reaching patent litigation are subject to losing their patent rights to a defensive claim of patent misuse. However, defendants find it difficult to charge patent trolls with misuse because the antitrust violations typically involved require significant market power on the part of the patent holder. Nevertheless, manufacturers do use various tactics to limit their exposure to patent trolls. Most have broader uses as well for defending their technologies against competitors. These include:
- Design arounds can be a defense against patent trolls. The amount of license fee that a patent troll can demand is limited by the alternative of the cost of designing around the troll's patent(s).
- Patent watch. Companies routinely monitor new patents and patent applications, most of which are published, to determine if any are relevant to their business activities.
- Clearance search. A standard practice is to perform a clearance search for patents or pending patent applications that cover important features of a potential product, before its initial development or commercial introduction. For example, a search by Thomas Edison uncovered a prior patent by two Canadian inventors, Henry Woodward and Mathew Evans for carbon filament in a non-oxidizing environment, (U.S. Patent 181,613), the type of light bulb Edison wanted to develop. Edison bought the patent for US$5,000 ($118,948 in present-day terms) to eliminate the possibility of a later challenge by Woodward and Evans.
- Opposition proceeding. In Europe (under the European Patent Convention), any person may initiate proceedings to oppose a European patent. There is a more limited process in the United States, known as a reexamination. As an example, Research In Motion, filed reexaminations against broad NTP, Inc. patents related to BlackBerry technology.
- Litigation. Whereas some companies acquiesce to a troll's demands, others go on the offensive by challenging the patents themselves, for example by finding prior art that invalidates their patentability. They may also broadly challenge whether the technology in question is infringing, or attempt to show patent misuse. If successful, such a defense not only wins the case at hand but destroys the patent troll's underlying ability to sue. Knowing this, the patent troll may back down or lessen its demands.
- Early settlement. An early settlement is often far less expensive than litigation costs and later settlement values.
- Patent infringement insurance. Insurance is available to help protect companies from inadvertently infringing a third party's patents.
- Defensive patent aggregation, the practice of purchasing patents or patent rights from patent holders so they don't end up in the hands of an individual or enterprise that can assert them. Increasingly aggregations are focused on purchasing patents and patent rights off the open market, or out of NPE assertion and litigation, which directly impact the businesses of the aggregation's members. The aggregator then provides members a broad license to everything it owns in exchange for an annual fixed-fee.
Patent defense companies have been formed In order to counteract problems caused by patent trolls in the high technology industry:
- A group of 11 high-tech companies including Cisco Systems, Ericsson, Google, Hewlett-Packard, and Verizon formed in 2008 Allied Security Trust with the goal of identifying and obtaining key patents prior to falling into the hands of patent trolls.
- In 2008 RPX Corporation introduced the RPX Defensive Patent Aggregation service to help e-commerce, financial services, hardware manufacturing, networking, software, and wireless companies reduce the risk of NPE assertion and litigation by purchasing patents off the open market.
Criticism of the term 
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- Overbreadth. Defining trolls broadly as patent holders that do not practice or promote the patented invention includes holding companies, most U.S. universities and some individual inventors (e.g. Thomas Edison). Some of these entities might not intend to profit from the tactics described above: For instance, large businesses typically have separate licensing departments, and may have separate patent holding companies, that are distinct from their research and development operations.
- Misapplied. Accusations of trolling may be conflated with broader criticisms of the patent office, or of patent rights in general, by those who claim the patent system is "broken", when in fact problems like poor quality patents, and patent thickets, are issues compounded by patent trolling, but distinct from it. Critics of the term argue that it is misguided to use it to criticize the patent system, because there are already mechanisms in place to restrain troll-like behavior. The two primary factors are the limited patent term and the obligation to disclose. However, others, such as former Assistant Attorney General Viet Dinh, make the case that the need for patent reform is made all the stronger by the existence of patent trolls who exploit vulnerabilities in the existing patent law.
- Political agenda. The term is used in a partisan manner by companies seeking to gain benefit at trial or by public relations by accusing competitors of being trolls, and also those objecting to or wanting to change the current patent laws on equitable grounds Nathan Myhrvold, the co-founder of Intellectual Ventures, an alleged patent troll firm, accused the use of the expression "patent troll" as primarily a public relations tactic that large corporations use to intimidate individual inventors in an effort to tilt the playing field in their favor. Parties that themselves actively enforce and license patents they do not practice, may criticize other companies for trolling when it suits their interest to do so.
- Legality of conduct Under US law patent owners need not commercialize the invention to enforce their patents. Patent owners may negotiate any royalty others can be convinced to pay in exchange for a license to not be prohibited from making, using or selling the patented invention, but the only right conferred by holding a US patent is the right to sue to prevent others from making, using or selling the invention or to collect damages for the breach of that right (UK and European patent law, by contrast, contains provisions for compulsory licenses). Moreover, the owner of a patent need not be the inventor. Patents are legally transferrable in the sense that they can be bought, sold and licensed to entities other than the inventor(s).
See also 
- Copyright troll
- Defensive patent aggregation
- Patent monetization
- Patent war
- Stick licensing
- Submarine patent
- Trademark troll
References and notes 
- Jones, Miranda. Casenote. Permanent injunction, a remedy by any other name is patently not the same: how eBay v. MercExchange affects the patent right of non-practicing entities (eBay v. MercExchange, L.L.C., 126 S. Ct. 1837, 2006.) 14 Geo. Mason L. Rev. 1035-1070 (2007)
- "patent troll". wordspy. Retrieved 2007-07-26.
- "The Original Patent Troll Returns". Intellectual Property Today. May 8, 2007.
- Brenda Sandburg (July 30, 2001). "You may not have a choice; Trolling for Dollars" (PDF). The Recorder.
- Joff Wild (August 22, 2008). The real inventors of the term "patent troll" revealed. IAM Magazine.
- Meet the Original Patent Troll, IP Law & Business (via law.com), July 20, 2006
- R.G. (December 5, 2005). "Has the Enemy of Patent Trolls Become One". Ziff Davis. Retrieved 2007-07-27.
- Subramanian, Sujitha (2008). "Patent Trolls in Thickets: Who is Fishing Under the Bridge?". European Intellectual Property Review.  (5) (Sweet & Maxwell). pp. 182–188
- Alexander Poltorak. "On 'Patent Trolls' and Injunctive Relief"., ipfrontline.com, May 12, 2006
- "EPO Scenarios for the Future, 2005, Glossary" (PDF). European Patent Office. Retrieved 2007-07-27.
- Morag Macdonald, "Beware of the troll". The Lawyer. September 26, 2005. Retrieved 2007-07-27.
- Danielle Williams and Steven Gardner (April 3, 2006). Basic Framework for Effective Responses to Patent Trolls, (PDF). North Carolina Bar Association, Intellectual Property Law Section.
- What is a troll patent and why are they bad?, By TJ Chiang (Professor at George Mason Law School), March 6, 2009
- Craig Tyler, Patent Pirates Search For Texas Treasure, Texas Lawyer, September 20, 2004
- Jones, Miranda (2007). "Casenote: Permanent injunction, a remedy by any other name is patently not the same: how eBay v. MercExchange affects the patent right of non-practising entities". George Mason Law Review 14: 1035–1040.
- Yeh, Brian T. (August 20, 2012). "An Overview of the "Patent Trolls" Debate". Congressional Research Service. Retrieved January 23, 2013.
- Katherine E. White, Preserving the Patent Process to Incentivize Innovation in Global Economy, 13 Syracuse Sci. & Tech. L. Rep. 27 (2006).
- Or non-manufacturing entity.
- Gerard Magliocca, Blackberries and Barnyards: Patent Trolls and the Perils of Innovation, 82 Notre Dame L. Rev. 1809 (2007).
- Susan Walmsley Graf, Improving Patent Quality Through Identification of Relevant Prior Art: Approaches to Increase Information Flow to the Patent Office, 11 Lewis & Clark L. Rev. 495 (2007), footnote 8.
- FTC Report, March 2011, The Evolving IP Marketplace : Aligning Patent Notices and Remedies with Competition, page 8, footnote 5; page 50, footnote 2.
- JAMES F. MCDONOUGH III (2007). "The Myth of the Patent Troll: An Alternative View of the Function of Patent Dealers in an Idea Economy". Emory Law Journal. Retrieved 2007-07-27. Unknown parameter
- Michael Kanellos (March 3, 2006). "Patent auctions: Lawyer's dream or way of the future?". zdnet. Archived from the original on 2007-04-03. Retrieved 2007-07-27.
- Craig Tyler (September 24, 2004). Patent Pirates Search For Texas Treasure (PDF). Texas Lawyer. Retrieved 2007-07-27.
- Justin Watts (June 2007). "Waiting for Godot". Patent World.
- Joff Wild (2008-05-08). "Mutual recognition raises its head as EPO boss says backlog won't be mastered". Intellectual Asset Management Magazine. Retrieved 2008-06-19.
- USPTO 2005 annual report, Table 13A and 13B
- Robert A. Saltzberg and Mehran Arjomand, Reexaminations Increase in Popularity, Morrison and Foerster, September 2007
- Patent Reexamination by Robert J. Yarbrough. Consulted on November 12, 2011.
- "USPTO: Broadest Claims Forgent Asserts Against JPEG Standard Invalid". Groklaw.net. May 26, 2006. Retrieved 2007-07-21.
- "JPEG Patent's Single Claim Rejected (And Smacked Down For Good Measure)". Techdirt.com. 2008-08-01. Retrieved 2011-05-29.
- Kawamoto, Dawn (April 22, 2005). "Graphics patent suit fires back at Microsoft". CNET News. Retrieved 2009-01-28.
- Matthew Sag and Kurt W. Rohde (August 21, 2006). "Patent Reform and Differential Impact". Northwestern University.
- Don Clark (March 9, 2006). "Inventors See Promise In Large-Scale Public Patent Auctions". the Wall Street Journal Online. Retrieved 2007-07-27.
- IPFrontline Staff (March 11, 2006). "Making Innovation Pay". ipFrontline.com. Retrieved 2007-07-27.
- Nicholas Varchaver,Who's afraid of Nathan Myhrvold?, Fortune Magazine, June 26, 2006
- Interview With Chief Judge Paul R. Michel On US Patent Reform, Intellectual Property Watch, July 19, 2011. Consulted on August 8, 2011.
- Sam Williams (February 6, 2006). "A Haven for Patent Pirates". Technology Review. Retrieved 2007-07-07.
- 35 U.S.C. § 284
- Jessica Holzer (May 16, 2006). "Supreme Court Buries Patent Trolls". Forbes.com. Retrieved 2007-07-27.
- Intel Corp. v. Advanced Micro Devices, Inc., 12 F.3d 908 (9th Cir. 1993) cert. denied, 512 U.S. 1205 (1994)
- For example, see Intellectual Ventures
- Caroline Horton Rockafellow. "Examining Patent Troll Debate: Should They Be An Endangered Species?". Local Tech Wire. Retrieved 2007-07-27.
- Patent 'Troll' Tactics Spread, The Wall Street Journal, July 8, 2012
- Bessen, James E. and Meurer, Michael J., The Direct Costs from NPE Disputes (June 28, 2012). Boston Univ. School of Law, Law and Economics Research Paper No. 12-34. Available at http://dx.doi.org/10.2139/ssrn.2091210
- Nick Bilton, An Explosion of Mobile Patent Lawsuits, The New York Times, Bits (blog), March 4, 2010. Consulted on March 4, 2010.
- Nathan Vardi (May 7, 2007). "Patent Pirates". Forbes Magazine. Retrieved 2007-07-27.
- Jose Cortina (July 26, 2006). "Antitrust Considerations In Patent Enforcement: A Patent Doesn't Mean Grant Of Monopoly Power". Local Tech Wire. Retrieved 2007-07-27.
- Golden, John M. (2007). "‘Patent Trolls’ and Patent Remedies". Texas Law Review 85 (7): 2111–2161 [p. 2130]. SSRN 991698.
- Staff. Consumer Price Index (estimate) 1800–2012. Federal Reserve Bank of Minneapolis. Retrieved March 31, 2013.
- "In Fight Against Patent Trolls, A New Arrow in the Quiver". Wall Street Journal. November 24, 2008.
- Merritt, Rick (July 2, 2008). "Patent pools may flow in wake of latest alliance". EE Times. Retrieved July 6, 2008.
- Sharma, Amol; Clark, Don (September 17, 2008). "Tech Guru Riles the Industry by Seeking Huge Patent Fees". Wall Street Journal.
- "RPX, Can it Defend Against Patent Trolls". CNet. November 24, 2008.
- Judy Newman (May 9, 2006). "Innovators fear the patent trolls".
- "The Case for Abandoning the Term 'Patent Troll'". Archived from the original on 2007-09-29. Retrieved 2007-07-27.
-  Professor Viet Dinh, former Assistant Attorney General for Legal Policy, Dec. 3, 2007
- Nathan Myhrvold (March 30, 2006). "Inventors Have Rights, Too!". Wall Street Journal. Retrieved 2007-07-27.
- Stefanie Olsen (August 9, 2004). "Google, Yahoo bury the legal hatchet". CNET. Retrieved 2007-07-27.
- Michael Smith (October 11, 2006). "Patent Pirates only exist in Neverland" (PDF). Texas Lawyer. Retrieved 2007-07-27., Texas Lawyer, November 11, 2004
Further reading 
- Connell O'Neill, The Battle Over Blackberry: Patent Trolls and Information Technology, The Journal of Law, Information, and Science, 2008, Vol. 17, p. 99-133. 
- Maggie Shiels, Technology industry hits out at "patent trolls", BBC News, June 2, 2004. 
- Lorraine Woellert, A Patent War Is Breaking Out On The Hill, Business Week, July, 2005.
- Joe Beyers, Rise of the patent trolls, CNET News.com, October 12, 2005.
- Raymond P. Niro, The Patent Troll Myth, Professional Inventors Alliance web site, August 4, 2005.
- Raymond P. Niro, Who is Really Undermining the Patent System – "Patent Trolls" or Congress?. 6 J. Marshall Rev. Intell. Prop. L. 185 (2007).
- Jennifer Kahaulelio Gregory, "The Troll Next Door", 6 J. Marshall Rev. Intell. Prop. L. 292 (2007).
- Simon Phipps, On Cane Toads, Fire Ants and Patents, SunMink, February 13, 2005.
- Bakos, Tom, "Patent Trolls", Insurance IP Bulletin, Vol. 2005.3, June 2005. 
- Ferrill, Elizabeth, "Patent Investment Trusts: Let's Build a PIT to Catch the Patent Trolls", N.C. J. of Law & Tech., Vol 6, Iss. 2: Spring 2005.
- Kurt Leyendecker, "Patent Trolls!", Control, Protect & Leverage, A Leyendecker & Lemire Blog, March 14, 2006. 
- Steven Rubin (March, 2007). "Hooray for the Patent Troll!". IEEE Spectrum.
- Colleen Chien, Of Trolls, Davids, Goliaths, and Kings: Narratives and Evidence in the Litigation of High-Tech Patents, 87 N.C. L. Rev. 1571 (2009), available at SSRN. Summarized at Jotwell.
|Look up patent troll in Wiktionary, the free dictionary.|
- Scholarly article on nuisance value patent infringement lawsuits, Author: Ranganath Sudarshan
- When Patents Attack!, This American Life episode #441