PersonalWeb Tech LLC v. FAB Commerce & Design Inc

I. Executive Summary and Procedural Information

• Parties & Counsel:
  • Plaintiff: PersonalWeb Technologies LLC (Texas) & Level 3 Communications LLC (Delaware)
  • Defendant: Fab Commerce & Design Inc (Delaware)
  • Plaintiff’s Counsel: Stubbs, Alderton & Markiles, LLP
• Case Identification: 5:18-cv-03578, N.D. Cal., 10/04/2018
• Venue Allegations: The complaint alleges venue is proper because the action was transferred to the Northern District of California by the Judicial Panel on Multidistrict Litigation for consolidated pretrial proceedings. The original basis for venue was Defendant’s alleged regular and established place of business and acts of infringement in the Southern District of New York.
• Core Dispute: Plaintiff alleges that Defendant’s e-commerce website, "fab.com", infringes patents related to identifying and managing data using content-based identifiers, specifically through its use of the HTTP ETag protocol for web content caching.
• Technical Context: The technology concerns using cryptographic hashes to generate unique, content-dependent names for data files, a foundational technique for data deduplication, cache management, and content verification in distributed computing systems like content delivery networks (CDNs).
• Key Procedural History: The complaint notes that the last of the patents-in-suit has expired and that the allegations are directed to the time period before expiration, indicating the suit is for past damages only. Plaintiff also states it has previously successfully enforced its rights and granted non-exclusive licenses for the patents-in-suit.

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 Issued
2010-09-21	U.S. Patent No. 7,802,310 Issued
2012-01-17	U.S. Patent No. 8,099,420 Issued
2018-10-04	Complaint Filing Date

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 "’442 Patent").

The Invention Explained

• Problem Addressed: The patent’s background describes the inefficiency and unreliability of conventional data identification methods (e.g., file pathnames) in networked computer systems. These methods are context-dependent and bear no direct relationship to the actual content of the data, leading to problems with data duplication, cache synchronization, and integrity verification (Compl. ¶15; ’442 Patent, col. 2:13-27).
• The Patented Solution: The invention proposes a system where "data items" are identified by a substantially unique, content-based identifier called a "True Name" (’442 Patent, col. 5:8-12). This name is generated by applying a cryptographic function, such as a message digest or hash function (e.g., MD5, SHA), to the data item's content (’442 Patent, Abstract). This allows any computer on a network to identify, locate, and manage data based solely on its content, independent of its name or location, and enables the system to check for unauthorized or unlicensed copies of content (’442 Patent, Abstract; col. 5:8-12).
• Technical Importance: This approach provided a foundational method for data deduplication and content verification, which became critical for the efficiency and reliability of large-scale distributed storage and content delivery networks (Compl. ¶13, 16).

Key Claims at a Glance

• The complaint asserts independent claim 10 and dependent claim 11 (Compl. ¶51).
• 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 on a function of the file's contents.
  • Using that name to determine if a copy of the data file is present on one of the computers.
  • Determining if that present copy is an "unauthorized copy or an unlicensed copy" of the data file.

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 "’310 Patent").

The Invention Explained

• Problem Addressed: Similar to the ’442 Patent, the ’310 Patent addresses the problem of managing data in distributed systems where traditional naming conventions are inadequate for verifying data or controlling access (’310 Patent, col. 2:1-24).
• The Patented Solution: The patent describes a method for controlling content distribution between computers in a network. A "first computer" receives a request from a "second computer" which includes a "content-dependent name" (e.g., a hash) for a particular data item. Based on this name, the first computer determines if the content is "unauthorized or unlicensed." It then either permits the content to be provided to the second computer or denies it access (’310 Patent, Abstract; col. 41:1-26).
• Technical Importance: The invention applies the content-based naming concept directly to access control logic, a fundamental requirement for secure and efficient content delivery systems where authorization to use specific versions of content is critical (Compl. ¶13).

Key Claims at a Glance

• The complaint asserts independent claim 20 (Compl. ¶59).
• The essential elements of independent claim 20 are:
  • A computer-implemented method for controlling content distribution from a first computer to another in response to a request.
  • The request includes a "content-dependent name" of a data item, where the name is based on a function (like a hash) of the item's data.
  • Based on the content-dependent name, the first computer either: (A) permits the content to be provided or accessed if it is not determined to be "unauthorized or unlicensed," or (B) does not permit the content to be provided or accessed if it is determined to be "unauthorized or unlicensed."

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 (the "’420 Patent").
• Technology Synopsis: This patent describes a system for managing data access using content-dependent digital identifiers. The system determines one or more such identifiers for a data item and compares them to entries in one or more databases to selectively permit the data item to be made available for access across a network of computers (’420 Patent, Abstract). The invention focuses on a system-level implementation of the access control method using databases of content-based identifiers.
• Asserted Claims: The complaint asserts independent claim 166 and dependent claims 25, 26, 27, 29, 30, 32, and 34-36 (Compl. ¶66).
• Accused Features: The complaint accuses Defendant's system of web servers with databases containing ETag values associated with URIs for asset files, which are used to control access to authorized file content by downstream caches (Compl. ¶71).

III. The Accused Instrumentality

Product Identification

The website located at "fab.com" and its associated systems and methods for providing webpage content (Compl. ¶31).

Functionality and Market Context

The complaint alleges the accused instrumentality operates as a web content delivery system that serves webpages composed of base HTML files and various "asset files" such as images and scripts (Compl. ¶36). To improve efficiency, the system uses the HTTP ETag mechanism for caching. A content-based ETag value is allegedly generated for asset files by applying a hash function to the file's content (Compl. ¶37). When a browser requests a previously downloaded asset, it sends a "conditional" GET request that includes the ETag in an "If-None-Match" header (Compl. ¶40, 43). The server checks this ETag against its current version; if they match, it sends a "304 Not Modified" response, instructing the browser to use its cached copy. If they do not match, it sends the new file and a new ETag (Compl. ¶45, 46). The complaint alleges that Defendant contracts with Amazon's S3 service to store and serve certain asset files, with S3 generating the content-based ETags on Defendant's behalf (Compl. ¶38). This system allegedly reduces bandwidth and server load, allowing for efficient content updates (Compl. ¶35). The complaint references Exhibit 1 as an example of an asset file served by S3 with a content-based ETag generated on behalf of the Defendant (Compl. ¶47).

IV. Analysis of Infringement Allegations

’442 Patent 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 or obtains ETag values for its web asset files. These ETags are allegedly created by applying a hash function to the contents of the files, either by Defendant's own system or by Amazon S3 on its behalf.	¶53	col. 13:5-15
determining, using at least the name, whether a copy of the data file is present on at least one of said computers	Defendant’s origin servers or intermediate cache servers receive a browser's conditional GET request containing a URI and an ETag, and determine if a file corresponding to that URI is present.	¶54	col. 40:24-28
determining whether a copy of the data file that is present... is an unauthorized copy or an unlicensed copy of the data file	The server compares the ETag from the browser's request with its stored ETag for the file. A match means the browser's copy is "authorized" for use; a mismatch means it is "unauthorized," triggering the delivery of a new version.	¶55	col. 32:45-52

• Identified Points of Contention:
  • Scope Questions: A central issue may be the construction of "unauthorized copy or an unlicensed copy." The complaint equates this with an outdated file in a cache validation context (Compl. ¶55). A potential dispute is whether this term, used in a patent titled for "Licensed Content," is limited to an intellectual property rights context or can be read more broadly to cover technical cache coherency.
  • Technical Questions: The complaint alleges that Defendant "caused" various computers in the network to perform the claimed steps (Compl. ¶53, 54). The analysis may question whether Defendant's role in the distributed system, particularly its use of third-party services like Amazon S3 (Compl. ¶38), constitutes direct infringement for each step of the claimed method.

’310 Patent 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 obtained by a first device... from a second device..., the request including at least a content-dependent name...	An upstream cache or origin server ("first computer") controls distribution of an asset file to a browser or downstream cache ("second computer") in response to a conditional GET request containing a content-based ETag ("content-dependent name").	¶61	col. 40:22-38
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 the server determines the ETag from the request matches its own, it sends an HTTP 304 response, thereby "permitting" the browser to access its local copy. If the ETags do not match, it sends an HTTP 200 response with new content, "not permitting" access to the old, outdated content.	¶62	col. 41:1-26

• Identified Points of Contention:
  • Scope Questions: As with the ’442 Patent, a key question is whether "unauthorized or unlicensed" can be construed to cover an outdated cache entry.
  • Technical Questions: A potential point of contention is whether sending an HTTP 304 "Not Modified" response meets the claim limitation of "permitting the content to be provided to or accessed by the at least one other computer." The argument could be made that in this scenario, no content is actually "provided" by the first computer; rather, the first computer is authorizing the use of content already possessed by the second computer.

V. Key Claim Terms for Construction

• The Term: "unauthorized copy or an unlicensed copy" / "unauthorized or unlicensed"
• Context and Importance: The viability of the infringement allegations for both the ’442 and ’310 patents may depend on construing this term to encompass an outdated or invalid cached file. Practitioners may focus on this term because the patents' titles and specifications repeatedly reference "licensed content" and "licensing," suggesting a narrower, rights-management context.
• Intrinsic Evidence for Interpretation:
  • Evidence for a Broader Interpretation: The patents describe the invention’s utility for maintaining cache consistency, where an outdated file could be considered "unauthorized" for use by the system operator (’442 Patent, col. 3:1-6, col. 36:58-65).
  • Evidence for a Narrower Interpretation: The title of the ’442 Patent is "Enforcement and Policing of Licensed Content..." and the specification includes an extended mechanism for "Track for licensing purposes" (’442 Patent, col. 32:45-65). This language may support a construction limited to intellectual property licensing and authorization.

VI. Other Allegations

• Indirect Infringement: The complaint does not plead separate counts for indirect infringement. However, the factual allegations state that Defendant "instructed" browsers and cache servers to perform certain steps (Compl. ¶40) and "caused" servers to perform others (Compl. ¶53), which may suggest an underlying theory of inducement. The complaint alleges these instructions are provided by responding to HTTP GET requests with ETags, which directs downstream caches on how to handle future requests (Compl. ¶40).

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

• A core issue will be one of "definitional scope": can the term "unauthorized or unlicensed," which appears in patents heavily focused on "licensed content," be construed to cover the technical state of an "outdated file" in a standard web caching protocol?
• A key evidentiary question will be one of "functional mismatch": does the accused system's standard HTTP 304 "Not Modified" response—which authorizes the use of content already present on a user's device—meet the claim limitation of "permitting the content to be provided," or is there a fundamental difference in technical operation?
• A third question will concern "agency and direct infringement": given the allegation that a third party (Amazon S3) generates content-based identifiers on Defendant's behalf, the case may explore whether Defendant's actions constitute direct infringement of all claimed steps or if Plaintiff must establish the elements of indirect infringement.