Network Monitoring

I. Executive Summary and Procedural Information

• Parties & Counsel:
  • Plaintiff: Network Monitoring LLC (Texas)
  • Defendant: Trivago N.V. (Netherlands)
  • Plaintiff’s Counsel: Fabricant LLP; Truelove Law Firm, PLLC
• Case Identification: 2:21-cv-00150, E.D. Tex., 04/29/2021
• Venue Allegations: Venue is alleged to be proper because Defendant is a foreign corporation not residing in the United States, which permits suit in any judicial district.
• Core Dispute: Plaintiff alleges that Defendant’s online hotel metasearch service infringes two patents related to systems and methods for tracking online user activity by rewriting URLs.
• Technical Context: The technology concerns methods for monitoring user navigation between different websites, a foundational capability for online advertising, analytics, and monetization models like cost-per-click.
• Key Procedural History: The complaint does not mention any prior litigation, IPR proceedings, or licensing history related to the Asserted Patents.

Case Timeline

II. Technology and Patent(s)-in-Suit Analysis

U.S. Patent No. 9,058,416 - "System and Method for Detecting and Reporting Online Activity using Real-Time Content-Based Network Monitoring," Issued June 16, 2015

The Invention Explained

• Problem Addressed: The patent describes the difficulty in the early 2000s of obtaining reliable data about online user activity, particularly transactional data, as it occurs across multiple, independently operated websites. Existing solutions like client-side meters were described as cumbersome, while server-log analysis was limited to a single website and lacked granular detail. (’416 Patent, col. 1:15-2:54).
• The Patented Solution: The invention proposes a centralized tracking system that intercepts and analyzes network traffic between a user's browser and web servers. A key embodiment uses a "URL-rewriting proxy agent" which works by "rewriting URLs such that the original URL is encoded as part of the path of the proxy URL." This allows the system to capture information from the data stream, even across different websites, without requiring software installation on the user's computer or modification of the target websites. (’416 Patent, Abstract; col. 6:19-29).
• Technical Importance: This approach provided a method for independent, cross-site tracking of user behavior, a significant challenge for the then-nascent fields of web analytics and performance-based online advertising. (’416 Patent, col. 4:1-15).

Key Claims at a Glance

• The complaint asserts at least independent claim 1. (Compl. ¶¶29-30).
• Claim 1 (Method):
  • A method of capturing information about a user browser's activity on a tracking system.
  • Providing the user browser a web page with a URL specifying an address of the tracking system and information specifying a URL on a web server.
  • Upon the tracking system receiving a request, determining the web server URL from that request.
  • Identifying, extracting, and storing in a database captured information indicating the browser requested the web server URL.
  • Forming parameter data from the database based on pre-determined selection parameters.
  • Encoding an original URL as part of the tracking system URL path to construct a rewritten URL.
  • Embedding the rewritten URL in the response so a browser request is sent to the tracking system.
  • Causing the web page specified by the web server URL to be returned to the user browser.
• The complaint does not explicitly reserve the right to assert dependent claims but makes general allegations of infringement of "one or more claims." (Compl. ¶29).

U.S. Patent No. 9,680,946 - "System and Method for Detecting and Reporting Online Activity using Real-Time Content-Based Network Monitoring," Issued June 13, 2017

The Invention Explained

• Problem Addressed: As a continuation of the '416 Patent, the '946 Patent addresses the same technical problem: the difficulty of tracking user activity and transactions across a plurality of websites using prior art methods. (’946 Patent, col. 1:19-2:65).
• The Patented Solution: The '946 Patent describes a similar solution centered on a tracking system that intercepts client-server communications. The specification again highlights the use of a proxy agent to capture HTTP transmissions, rewrite URLs by encoding the original destination, and thereby monitor user activity without modifying browsers or end-user websites. (’946 Patent, Abstract; col. 6:8-25).
• Technical Importance: The technology aimed to enable robust, independent, and detailed tracking of online commercial activity, such as e-commerce purchases and airline reservations, which was not easily achievable with existing tools. (’946 Patent, col. 3:30-41).

Key Claims at a Glance

• The complaint asserts at least independent claim 1. (Compl. ¶¶38-39).
• Claim 1 (Apparatus):
  • A computer programmed digital electrical tracking system apparatus connected to a user browser and a web server.
  • The apparatus is adapted to perform the same core steps as method claim 1 of the ’416 Patent (providing a URL, determining a web server URL, extracting information, forming parameter data, encoding an original URL, embedding the rewritten URL, and causing the destination page to be returned).
  • It adds a final functional limitation: "provide profiling and analysis of at least one session."
• The complaint makes general allegations of infringement of "one or more claims." (Compl. ¶38).

III. The Accused Instrumentality

Product Identification

The accused instrumentalities are Defendant's website, www.trivago.com, and its supporting backend computer systems, including web servers and databases, collectively referred to as the "Accused Infrastructures." (Compl. ¶16).

Functionality and Market Context

• The Accused Infrastructures provide an online metasearch service for hotels and lodging. (Compl. ¶¶3, 16). The complaint alleges that when a user conducts a search and selects an offer from a third-party booking site, the Accused Infrastructures do not direct the user to the third-party site immediately. (Compl. ¶21). Instead, the system generates and sends the user's browser to an intermediate "Trivago URL." This URL is alleged to contain an encoded version of the original destination URL (e.g., for a hotel on Orbitz.com) along with other tracking information. (Compl. ¶¶17, 21). After processing this intermediate request, the system redirects the user to the third-party website. (Compl. ¶22). This process allegedly allows the Defendant to capture information about user activity and monetize searches, such as through a cost-per-click model. (Compl. ¶16).
• The complaint includes a screenshot from the Trivago website showing hotel search results. (Compl. ¶22, p. 9). This visual illustrates the user-facing interface that initiates the allegedly infringing process.

IV. Analysis of Infringement Allegations

’416 Patent Infringement Allegations

’946 Patent Infringement Allegations

Identified Points of Contention

• Scope Questions: A central question may be whether Trivago's integrated metasearch service constitutes the "tracking system" envisioned by the patents. The patents describe a system that can monitor traffic between a user and third-party sites, which could raise the question of whether the claims read on a system that is tracking referrals originating from its own platform.
• Technical Questions: The infringement case may depend on evidence demonstrating that Trivago's system performs the specific "encoding" step as claimed. While the complaint provides a long URL with an "enc=" parameter (Compl. ¶22), the precise technical mechanism by which this parameter is generated and used to store and retrieve the "original URL" will be a key factual issue.

V. Key Claim Terms for Construction

The Term

"tracking system"

Context and Importance

This term appears in the preamble of the asserted independent claims of both patents. Its construction is critical because it defines the infringing entity. The dispute may turn on whether the "tracking system" must be architecturally distinct from the primary web server a user is visiting, or if it can be an integrated part of that server's own infrastructure that monitors click-throughs to other sites.

Intrinsic Evidence for Interpretation

• Evidence for a Broader Interpretation: The claims do not explicitly require the "tracking system" to be a separate third-party entity. Claim 1 of the ’416 Patent simply recites "a computer programmed digital electrical tracking system," which is not structurally limited. (’416 Patent, col. 23:18-20). This language could support a reading that covers any set of components performing the claimed tracking functions.
• Evidence for a Narrower Interpretation: The specification frequently describes the invention in the context of a proxy that sits between a user and multiple, unaffiliated web servers. For example, it describes a "portal site" with a directory of merchants that rewrites URLs to "direct users through the URL-proxy." (’416 Patent, col. 6:51-56). This could support an argument that the invention is directed to a system that tracks a user's journey between separate domains, rather than an integrated platform tracking its own outbound referrals.

VI. Other Allegations

Indirect Infringement

The complaint alleges that Defendant induces infringement by providing the Accused Infrastructures to end users. By clicking the allegedly rewritten URLs, end users' browsers directly perform steps of the claimed method, which is allegedly encouraged and enabled by Defendant. (Compl. ¶¶31-33, 40-42).

Willful Infringement

The complaint alleges that Defendant had knowledge of the patents and either knowingly infringed or was willfully blind to the infringement. The pleading does not state the basis for this alleged knowledge (e.g., a notice letter), but claims the infringement was and continues to be willful. (Compl. ¶¶32-33, 41-42, 45(b)).

VII. Analyst’s Conclusion: Key Questions for the Case

• A core issue will be one of architectural scope: does the term "tracking system," as defined by the patents, cover an integrated metasearch platform like Trivago's tracking its own outbound user clicks, or is it limited to a system that is architecturally separate from the websites being monitored?
• A key evidentiary question will be one of technical mechanism: what factual evidence will be presented to prove that Trivago's use of redirect URLs and encoded parameters constitutes "encoding an original URL as part of the tracking system URL path" in the specific manner required by the asserted claims?
• A further question arises from the distinction between the asserted claims: does Trivago's use of captured information rise to the level of "profiling and analysis of at least one session" as explicitly required by claim 1 of the ’946 Patent, a limitation not present in claim 1 of the ’416 Patent?