DCT
5:18-cv-05966
PersonalWeb Tech LLC v. RetailMeNot Inc
Key Events
Complaint
I. Executive Summary and Procedural Information
- Parties & Counsel:
- Plaintiff: PersonalWeb Technologies, LLC (Texas) and Level 3 Communications, LLC (Delaware)
- Defendant: RetailMeNot, Inc. (Delaware)
- Plaintiff’s Counsel: Farnan, LLP
- Case Identification: 5:18-cv-05966, D. Del., 09/13/2018
- Venue Allegations: Plaintiff alleges venue is proper in the District of Delaware because Defendant is incorporated in Delaware and has committed acts of infringement within the district.
- Core Dispute: Plaintiff alleges that Defendant’s website, retailmenot.com, and its underlying content delivery architecture infringe patents related to identifying, managing, and controlling access to data using content-based identifiers.
- Technical Context: The technology concerns using cryptographic hashes to generate unique identifiers for data files, enabling efficient de-duplication, verification, and access control in distributed computer networks, a foundational concept for cloud computing and content delivery networks.
- Key Procedural History: Plaintiff notes that the patents-in-suit have been successfully enforced against third parties, resulting in settlements and non-exclusive licenses. The complaint also states that the last of the patents-in-suit has expired and that the allegations are directed to the time period before expiration. Public records indicate the asserted patents have undergone multiple post-grant proceedings, including ex parte reexaminations and an inter partes review, which have resulted in the cancellation and confirmation of various claims.
Case Timeline
| Date | Event |
|---|---|
| 1995-04-11 | Earliest Patent Priority Date (’442, ’310, ’420 Patents) |
| 2005-08-09 | U.S. Patent No. 6,928,442 Issues |
| 2010-09-21 | U.S. Patent No. 7,802,310 Issues |
| 2012-01-17 | U.S. Patent No. 8,099,420 Issues |
| 2018-09-13 | Complaint Filed |
II. Technology and Patent(s)-in-Suit Analysis
U.S. Patent No. 6,928,442 - "Enforcement and Policing of Licensed Content Using Content-Based Identifiers"
- Patent Identification: U.S. Patent No. 6,928,442, "Enforcement and Policing of Licensed Content Using Content-Based Identifiers," issued August 9, 2005.
The Invention Explained
- Problem Addressed: The patent's background describes the inefficiency of conventional data identification systems that rely on context-dependent names and locations (e.g., file paths) (ʼ442 Patent, col. 2:4-13). In large networks, this can lead to data duplication, difficulty verifying data integrity, and challenges in managing data when the same name refers to different data items or different names refer to the same data item (ʼ442 Patent, col. 2:14-18).
- The Patented Solution: The invention proposes a system where data items are identified by a "substantially unique" identifier derived from the content of the data itself, which the patent calls a "True Name" (ʼ442 Patent, col. 6:7-11). This identifier is generated by applying a function, such as a cryptographic hash (e.g., MD5, SHA), to the sequence of bits comprising the data item (ʼ442 Patent, Abstract). This content-based identifier is independent of name, origin, or location, allowing for efficient management, de-duplication, and integrity verification in distributed systems (ʼ442 Patent, col. 3:7-24).
- Technical Importance: This approach provided a method for reliably identifying and managing identical pieces of data across disparate systems without relying on fragile naming conventions, a key requirement for scalable distributed storage and content delivery (Compl. ¶11, 13).
Key Claims at a Glance
- The complaint asserts independent claim 10 and dependent claim 11 (Compl. ¶48).
- The essential elements of independent claim 10 are:
- A method in a system with files distributed across multiple computers.
- Obtaining a name for a data file based at least in part on a function of the file's contents.
- Using that name to determine if a copy of the data file is present on at least one of the computers.
- Determining if a present copy of the data file is an unauthorized or unlicensed copy.
U.S. Patent No. 7,802,310 - "Controlling Access to Data in a Data Processing System"
- Patent Identification: U.S. Patent No. 7,802,310, "Controlling Access to Data in a Data Processing System," issued September 21, 2010.
The Invention Explained
- Problem Addressed: The patent addresses the challenge of managing and controlling access to data in distributed systems where traditional context-based naming conventions are insufficient for ensuring data integrity and proper authorization (ʼ310 Patent, col. 2:40-52).
- The Patented Solution: The invention describes a method for controlling content distribution using content-dependent names. A first device (e.g., an origin or cache server) receives a request from a second device (e.g., a browser) that includes a content-dependent name for a data item ('310 Patent, col. 2:48-54). The first device uses this name to determine if the requested content is "unauthorized or unlicensed" and, based on this determination, either permits or denies the content from being provided to or accessed by the other computer ('310 Patent, Abstract; col. 2:54-61).
- Technical Importance: This method provides a framework for efficiently managing access rights and content validity in a distributed network, ensuring that clients and caches only use authorized versions of data (Compl. ¶57).
Key Claims at a Glance
- The complaint asserts independent claim 20 (Compl. ¶56).
- The essential elements of independent claim 20 are:
- A computer-implemented method in a system with multiple computers.
- Controlling content distribution from a first computer to another in response to a request from a second device.
- The request includes a content-dependent name of a data item, where the name is based on a hash or message digest function of the item's data.
- Based on the content-dependent name, the first device either permits access if the content is not determined to be unauthorized/unlicensed, or does not permit access if it is determined to be unauthorized/unlicensed.
Multi-Patent Capsule: U.S. Patent No. 8,099,420 - "Accessing Data in a Data Processing System"
- Patent Identification: U.S. Patent No. 8,099,420, "Accessing Data in a Data Processing System," issued January 17, 2012.
- Technology Synopsis: This patent discloses a system for accessing data in a distributed processing environment. The system determines content-dependent digital identifiers for data items and then selectively permits access based on whether those identifiers correspond to entries in one or more databases ('420 Patent, Abstract). This enables a system to ensure that computers in a network only access authorized content (Compl. ¶67-68).
- Asserted Claims: Independent claim 166 and dependent claims 25, 26, 27, 29, 30, 32, and 34-36 are asserted (Compl. ¶63).
- Accused Features: The complaint accuses Defendant’s system of web servers, caches, and software frameworks that use content-based ETags stored in databases to manage and authorize access to webpage and asset files (Compl. ¶64, 68).
III. The Accused Instrumentality
Product Identification
The accused instrumentality is the "retailmenot.com" website and its underlying content distribution system, which comprises origin servers, intermediate cache servers, and endpoint browser caches (Compl. ¶29, 49).
Functionality and Market Context
The system is alleged to use the standard HTTP "ETag" mechanism to manage cached web content (Compl. ¶31). When a browser requests a webpage asset, it includes the ETag of any version it has cached in an "If-None-Match" header (Compl. ¶31, 39). An upstream server (either an intermediate cache or the origin server) compares this received ETag with the ETag of its current file version (Compl. ¶41, 51). If the ETags match, the server responds with an HTTP 304 (Not Modified) message, instructing the browser to use its cached copy (Compl. ¶41). If they do not match, the server sends an HTTP 200 (OK) response containing the new file content and its new ETag (Compl. ¶42). This process is alleged to reduce bandwidth and server load by avoiding the re-transmission of unchanged content and allowing content to be served from caches closer to the user (Compl. ¶33). No probative visual evidence provided in complaint.
IV. Analysis of Infringement Allegations
U.S. Patent No. 6,928,442 Infringement Allegations
| Claim Element (from Independent Claim 10) | Alleged Infringing Functionality | Complaint Citation | Patent Citation |
|---|---|---|---|
| obtaining a name for a data file, the name being based at least in part on a given function of the data, wherein the data used by the function comprises the contents of the particular file | Defendant's system generates ETag values for webpage and asset files by applying a hash function to the contents of those files. | ¶50 | col. 13:4-15 |
| determining, using at least the name, whether a copy of the data file is present on at least one of said computers | Defendant's servers receive a conditional GET request containing an ETag and URI, compare the received ETag to the stored ETag for that URI, and thereby determine if a copy of the content is present. | ¶51 | col. 1:57-60 |
| determining whether a copy of the data file that is present on a at least one of said computers is an unauthorized copy or an unlicensed copy of the data file | If the received ETag matches the server's ETag, the server determines the cached copy is authorized. If there is no match, the server determines the cached copy is unauthorized. | ¶52 | col. 1:60-63 |
U.S. Patent No. 7,802,310 Infringement Allegations
| Claim Element (from Independent Claim 20) | Alleged Infringing Functionality | Complaint Citation | Patent Citation |
|---|---|---|---|
| controlling distribution of content from a first computer to at least one other computer, in response to a request...the request including at least a content-dependent name of a particular data item...wherein the function comprises a message digest function or a hash function | An upstream server (first computer) receives a conditional GET request from a downstream browser or cache (second computer). The request includes an ETag (content-dependent name) that was generated by hashing the content of a data item. | ¶58 | col. 2:48-61 |
| based at least in part on said content-dependent name...the first device (A) permitting the content to be provided...if it is not determined that the content is unauthorized or unlicensed, otherwise, (B)...not permitting the content...if it is determined that the content is unauthorized or unlicensed | The upstream server compares the received ETag to its current ETag. A match (not unauthorized) results in an HTTP 304 response, permitting use of the cached content. A mismatch (unauthorized) results in an HTTP 200 response with new content, not permitting use of the old content. | ¶59 | col. 2:54-61 |
- Identified Points of Contention:
- Scope Questions: A central question may be whether the standard HTTP ETag functionality for cache validation falls within the scope of the patents' broader claims for content-based data identification and management. The defense may argue that ETags are part of a well-established, independent industry standard and that applying the patents' concepts to this specific protocol feature is not what was invented.
- Technical Questions: The infringement theory equates an ETag mismatch with a determination that a cached file is "unauthorized or unlicensed." A point of contention may be whether this technical check for content staleness meets the claim limitation, which could be interpreted to require a more explicit rights-management or security function rather than simple version control.
V. Key Claim Terms for Construction
The Term: "name being based at least in part on a given function of the data" ('442 Patent); "content-dependent name" ('310 Patent)
Context and Importance: The viability of the infringement case depends on whether the HTTP "ETag" value used by Defendant's system is construed as meeting this claim limitation. Practitioners may focus on this term because it is the foundational concept of the asserted patents.
Intrinsic Evidence for Interpretation:
- Evidence for a Broader Interpretation: The specification provides a very broad definition for a "data item" as any "sequence of bits" and describes the function as a "message digest or hash function" such as MD5 or SHA ('442 Patent, Abstract; col. 2:55-61), which aligns with common methods for generating ETags.
- Evidence for a Narrower Interpretation: The patents' detailed description is largely framed in the context of a novel file system architecture ('442 Patent, col. 5:14-20). A defendant may argue that the term should be limited to this disclosed context and not extended to cover functionality within a pre-existing, standardized protocol like HTTP.
The Term: "unauthorized copy or an unlicensed copy" ('442 Patent)
Context and Importance: Plaintiff's infringement theory equates a stale, cached file (identified by a non-matching ETag) with an "unauthorized" copy. The case may turn on whether this interpretation is supported.
Intrinsic Evidence for Interpretation:
- Evidence for a Broader Interpretation: The title of the '442 Patent, "Enforcement and Policing of Licensed Content," and its abstract, which states a "copy of a requested file is only provided to licensed (or authorized) parties," suggest a broad purpose of controlling access that could plausibly include preventing the use of outdated, and thus "unauthorized," versions.
- Evidence for a Narrower Interpretation: A party could argue that the terms "unauthorized" and "unlicensed" require a determination related to user permissions, copyrights, or explicit licenses, rather than merely checking if a file version is current. An ETag mismatch simply indicates the content is stale, which may not be synonymous with it being unlicensed.
VI. Other Allegations
- Indirect Infringement: The complaint alleges that Defendant "caused" downstream caches and browsers to perform claimed steps, such as obtaining ETags and sending conditional GET requests (Compl. ¶50, 58). It further alleges that Defendant's system "controlled the distribution of its website content" (Compl. ¶64). These allegations may support claims of induced and contributory infringement by providing the system and instructions (via HTTP headers) that cause third parties (browsers, caches) to perform the patented methods.
VII. Analyst’s Conclusion: Key Questions for the Case
- A core issue will be one of definitional scope: can the patents' central concept of a "content-dependent name" or "True Name," developed in the context of a novel data management system, be construed to read on the "ETag," a standardized entity used for cache validation within the established HTTP protocol?
- A key evidentiary question will be one of functional equivalence: does the accused system's comparison of ETags to determine if a cached file is stale perform the same function as "determining whether a copy... is an unauthorized copy or an unlicensed copy" as required by the claims, or is there a fundamental mismatch between technical version control and legal authorization?