A handful of US patents account for a disproportionate share of all patent troll activity. They get asserted against hundreds — sometimes thousands — of defendants. They drive whole NPE campaigns. They turn up again and again in demand letters because the shell-LLC plaintiffs behind them have figured out that the same patent can be re-used until someone proves it invalid.
Knowing the names matters. If your demand letter cites one of these, you are joining a campaign in progress — not facing a one-off claim. The plaintiff has a settlement playbook. The defenses that worked for prior defendants are public record. The invalidity grounds are sometimes already on file with PTAB.
This is a field guide to twelve of the patents that defined the modern patent troll era. Each one is in our database — click the patent number to see the full dossier (litigation history, prior art, obviousness analysis, derivative works).
Mass-defendant shakedowns
The defining business model of the modern NPE: file against dozens or hundreds of small defendants, ask for settlement amounts below the cost of mounting a defense, and rely on the asymmetry to harvest quiet payouts.
US 6,415,207 — Shipping & Transit (package tracking)
The EFF's "#1 worst patent troll in history" by case count. Shipping & Transit LLC and its predecessor Arrivalstar S.A. filed 500+ lawsuits between 2009 and 2018 over a vague patent on "vehicle status update notifications" — the idea of telling someone where their package or bus is. The targets were small e-commerce shops, transit agencies, even individual municipalities. Settlement asks were typically $25,000-$50,000. The campaign collapsed in 2018 when the company filed for bankruptcy after a string of fee awards under § 285. See § 285 fee shifting for the doctrine that ended this one.
US 7,010,508 and US 6,289,319 — Landmark Technology (online ordering)
Landmark Technology LLC ran one of the longest-running shakedown campaigns in patent troll history — over 20 years across two related patents on generic e-commerce ordering interfaces. 130 lawsuits and 1,176 demand letters documented by Washington and Idaho state AGs in their 2020 consumer-protection actions. The patents were eventually invalidated under Alice § 101 but only after extracting millions in $20,000-$65,000 settlements from small online retailers who couldn't afford to fight.
US 6,185,590 — MPHJ Technology ("scan to email")
MPHJ Technology Investments sent 16,465 demand letters between 2012 and 2014 to small businesses across the US, alleging that any office multifunction printer that emailed scanned documents infringed a 1990s-era patent. Settlement asks: $1,000-$1,200 per employee. The campaign drew investigations from multiple state attorneys general (Vermont, Nebraska, Minnesota) under consumer-protection statutes. The patent was PTAB-invalidated after Ricoh and HP filed IPR. MPHJ became one of the named villains in every "abusive patent troll" hearing on Capitol Hill in 2013-2014.
US 6,266,674 — eDekka (shopping cart user interface)
eDekka LLC filed 219 lawsuits against small online retailers — one of the highest single-year filing rates in patent troll history. The patent claimed an "interactive object storing and retrieving information" — i.e., a shopping cart. After being transferred to the Eastern District of Texas as part of a multi-district consolidation, Judge Rodney Gilstrap invalidated the patent under § 101 in 2015. Then, under Octane Fitness, he awarded fees against eDekka in nearly every case, citing the pattern of low-cost settlement demands as objectively unreasonable conduct.
US 8,069,073 — Lumen View Technology (decision-making engine)
The running example throughout this site, and the textbook case in the post-Octane era. Lumen View Technology LLC sued FindTheBest.com and ~20 other small marketplace sites over a vague "bilateral and multilateral decision-making" patent. FindTheBest fought back, and Judge Denise Cote invalidated the patent under § 101 in November 2013 — before Alice was even decided. Then she awarded attorneys' fees under § 285 and doubled them as a deterrent in October 2014. Read the full case study at Lumen View v. FindTheBest →.
Software "stupid patents"
The EFF's Stupid Patent of the Month series cataloged the worst offenders. Several of those patents became core assets in long-running NPE campaigns.
US 7,509,178 and US 8,112,504 — Personal Audio (podcasting)
Personal Audio LLC sued podcasters Adam Carolla, HowStuffWorks, CBS, and NBC in 2013, claiming the patent covered the basic act of distributing serialized audio content as podcasts — a practice that predated the patent by years. The EFF crowdfunded an IPR petition and won at PTAB in 2015. The Federal Circuit affirmed the invalidation in 2018. Personal Audio dropped its remaining suits.
US 6,795,918 — Wetro Lan (Wi-Fi range patent)
EFF Stupid Patent of the Month — a patent on the idea of having two different signal strengths in a wireless network (i.e., having an antenna). Wetro Lan LLC filed against most Wi-Fi router vendors and many businesses operating their networks. The patent has since expired; the campaign extracted settlements before invalidity could catch up with it.
US 5,490,216 — Uniloc (software activation/registration)
Uniloc filed 65+ lawsuits between 2010 and 2017 over a patent claiming the basic technique of asking software to phone home and verify its license — a practice every shrink-wrapped product since the 1980s used. Microsoft, Apple, Adobe, and most major software vendors were sued. PTAB invalidated the key claims in 2017 after combined IPRs filed by Microsoft and Symantec. Uniloc's later assertion campaigns have continued on different patents in the same portfolio.
Standard-essential patent (SEP) plays
The SEP world is different from the small-defendant shakedown world. Settlements are in the millions or hundreds of millions, but the legal threat is the same: pay or face an injunction in a country that grants them readily.
US 5,708,678 and US 7,490,263 — Conversant / Core Wireless (cellular SEPs)
Originally Nokia patents acquired by Conversant Intellectual Property Management (and before that, Mosaid). Used in the long-running Huawei v. Conversant FRAND litigation that went to the UK Supreme Court in 2020. The SEP licensing world runs on portfolio-wide rates negotiated under threat of country-specific injunctions; these are two of the patents that established the leverage.
US 6,502,135 and US 7,188,180 — VirnetX (secure VPN / FaceTime / iMessage)
VirnetX has extracted hundreds of millions of dollars in jury verdicts against Apple over these two patents, asserting that FaceTime, iMessage, and VPN On Demand infringe its 1990s-era secure-communication patents. Verdicts in the $454M, $625M, $439M, and $502M range — most reduced or reversed on appeal, then re-litigated, then re-affirmed. The case has become the touchstone for how long a patent campaign can run if the patent holder has the resources to keep fighting through reversals.
Verdicts that became cautionary tales
US 6,775,664 — Vringo / I/P Engine (Lycos search advertising)
The 2012 $1.05 billion verdict against Google in the Eastern District of Virginia for infringing search-advertising patents originally filed by Lycos. The Federal Circuit reversed in 2014 on obviousness grounds. The case demonstrated both the upside of the NPE business model (a one-billion-dollar verdict can fund the next decade of campaigns) and its fragility (the verdict was wiped out by KSR § 103 analysis).
US 5,412,730 — TQP Development (encryption)
A Spangenberg/IPNav-era patent on a generic encryption technique. 100+ lawsuits filed against any company using SSL/TLS-like connections — i.e., essentially the entire e-commerce sector. The patent owner, TQP Development LLC, won a 2013 jury verdict against Newegg for $2.3 million, but the Federal Circuit reversed in 2016 on prior-art grounds. The case is also notable for Lee Cheng, Newegg's then-Chief Legal Officer, becoming a vocal anti-troll spokesperson during the litigation.
What to do if you see one of these
If a demand letter cites one of the patents above — or your accused-product analysis matches one of these campaigns — the workflow is well-established:
- Check the patent dossier on this site. Each patent above has a six-section invalidity analysis already on file: summary, litigation history, prior art, obviousness, extensions, and derivative works. The work has been done. Click the patent number.
- Check PTAB. Many of these patents have ongoing or final IPR proceedings on file. The
/ptabbrowse tab on each patent shows every proceeding. Killed claims at PTAB are a defendant signal you can cite directly in district court (IPR estoppel explains what carries over). - Join the joint defense group. For multi-defendant campaigns, there is usually an active joint defense group sharing prior art, expert costs, and litigation strategy. Find it. The first 30 days after being sued is the right time to make contact (first 30 days).
- Don't settle for the demand-letter quote. The settlement quotes in these campaigns are calibrated against the cost of mounting a defense, not the value of the claim. If the underlying patent has invalidity exposure (and several above are already invalidated), the demand letter is a free option, not a price tag. See how to respond to a patent troll demand letter.
The data behind this list
The patents above were surfaced from a structured research pass against EFF's "Most Wanted" patents, Unified Patents' top-asserted lists, RPX's defensive-aggregator dockets, and US PACER docket counts. Every patent is in our database with a full invalidity dossier. Every asserter is on the /asserters page with case counts, ownership chains, and connected entities.
If you are looking at a patent that should be on this list and isn't, the database is open: any patent number you submit gets a six-section LLM-grounded dossier generated automatically. Drop the patent on the homepage, give it a few minutes, and the workup will be there.