XFN 1.1 profile
The XFN 1.1 profile establishes a standardized system for defining human relationships using the HTML rel attribute, creating a machine-readable social graph. According to the XFN 1.1 specification, these attributes—ranging from rel="friend" to rel="co-worker"—allow web browsers and software to identify the specific nature of a connection between two entities without requiring a centralized database.
How does XFN influence modern social graphs?
Modern social networks like LinkedIn and Meta use proprietary databases to track relationships, but XFN 1.1 pioneered the concept of “semantic” relationships. While a standard link only connects Page A to Page B, XFN adds a layer of meaning. For example, the XFN profile distinguishes between a colleague (someone in the same field) and a co-worker (someone at the same organization).
This distinction is now mirrored in the way professional platforms categorize “1st-degree” and “2nd-degree” connections. According to W3C standards, the use of metadata to describe the relationship between the source and the destination of a link is the foundation for the “Semantic Web.”
rel="met", implies that if Person A has met Person B, then Person B has necessarily met Person A.
What is the future of decentralized relationship mapping?
The industry is shifting toward the “Fediverse” and decentralized protocols like ActivityPub. These systems move away from a single company owning the social graph and return to the XFN philosophy of distributed identity. The XFN rel="me" attribute, which links a person to themselves at a different URL, serves as a primitive version of today’s Decentralized Identifiers (DIDs).
Future trends suggest a move toward “Verifiable Credentials.” Instead of simply claiming rel="colleague" in HTML, users may soon provide a cryptographically signed proof of employment. This transforms a simple metadata tag into a verified professional asset that remains portable across different platforms.
Comparing the two approaches: XFN 1.1 relies on trust and public declaration, whereas emerging Web3 standards rely on cryptographic verification. However, both prioritize the user’s ability to define their own identity outside of a corporate silo.
Why does relationship metadata matter for AI?
Large Language Models (LLMs) and AI agents require structured data to understand human context. The XFN 1.1 categories—such as kin, spouse, and acquaintance—provide a blueprint for how AI can map social hierarchies and influence networks.
According to Schema.org, the current industry standard for structured data, the evolution of XFN’s relationship tags allows AI to perform “entity resolution.” This is the process of determining if “John Doe” on a blog is the same “John Doe” listed as a co-worker on a corporate page. Without these specific relationship markers, AI is limited to guessing connections based on name similarity.
rel="me" links to your official social media profiles. This helps search engines verify that multiple accounts belong to the same individual.
How will privacy laws change social metadata?
The XFN 1.1 profile includes intimate categories like rel="crush" and rel="sweetheart". In the current regulatory environment, specifically under the GDPR in Europe, this type of “special category” data requires strict consent and protection.
Future implementations of relationship mapping will likely utilize Zero-Knowledge Proofs (ZKPs). This technology allows a person to prove a relationship exists (e.g., “I am a co-resident of this address”) without revealing the actual identity of the other person or the specific address. This solves the tension between the XFN goal of open connectivity and the modern requirement for absolute privacy.
Relationship Logic Comparison
| XFN Relation | Logic Type | Modern Equivalent |
|---|---|---|
sibling |
Symmetric / Transitive | Family Tree API |
me |
Exclusive / Symmetric | DID / Wallet Address |
colleague |
Symmetric / Often Transitive | LinkedIn Connection |
Frequently Asked Questions
What is XFN?
XFN (XHTML Friends Network) is a profile that uses the rel attribute in HTML links to describe human relationships in a way that machines can understand.
Is XFN still used today?
While less common in basic web design, the principles of XFN are integrated into Schema.org and the decentralized identity movements (DIDs) used by modern web protocols.
What does rel=”me” do?
It tells a search engine or a social bot that the linked page is another profile of the same person, helping to unify a digital identity across different platforms.
Can anyone use XFN tags?
Yes. Because XFN is based on standard HTML attributes, any website owner can add rel="friend" or rel="colleague" to their links without needing special software.
How does this differ from a “follow” on X (Twitter)?
A “follow” is typically asymmetric (one-way). XFN defines many relationships as symmetric, meaning the connection is mutual by definition.