XFML Specification


eXchangeable Faceted Metadata Language.

XFML Core is an open XML format for publishing and sharing hierarchical faceted metadata and indexing efforts. XFML Core is lightweight and easy to implement, yet uniquely powerful.

The XFML 1.0 spec is here.

A 2007 note for researchers: my take on XFML now is this: it was an interesting experiment, a so-so spec (not great, not bad either), but I now don't think there's demand for a format to exchange faceted data, and it hasn't been used much. It was fun though.


August 2007. Moved spec.

I lost the xfml.org domain, it got squatted, so I moved the spec to http://petervandijck.com/xfml/, which will continue to be its home in the foreseeable future.

February 14, 2003 Clarifications to XFML Core spec.

Added a few revisions to XFML Core. Clarifications only - the spec hasn't changed.

December 13, 2002 Revisions to XFML Core spec to remove minor inconsistencies with examples.

Added two revisions to XFML Core. Clarifications only - the spec hasn't changed.

October 08, 2002 XFML Core.

Today the XFML Core (aka XFML version 1.0) spec is officially published at http://purl.oclc.org/NET/xfml/core/. XFML Core is an XML language for sharing hierarchical faceted metadata and indexing efforts. XFML Core is a stable and frozen spec, and is permanently licensed to the public. XFML won’t solve all your metadata problems – it is focused on sharing indexing efforts with faceted metadata.

XFML was designed for power and simplicity. Coding an XFML export is often as easy as writing a template. Here is an XFML template for Moveabletype: http://poorbuthappy.com/ease/000494.html Drupal (http://drupal.org) has an XFML export module. Livetopics (http://www.novissio.com/products/liveTopics/liveTopics.html), a tool to add topical metadata to Radio Userland, also exports XFML: http://radio.weblogs.com/0107808/2002/10/07.html#a458

Once you publish your metadata as XFML, you can share it, and use it in other applications. Facetmap, an application to browse faceted metadata, was the first application to import XFML: http://facetmap.com. For example, you can export Livetopics as XFML and import it in Facetmap as in this example: http://radio.weblogs.com/0107808/2002/10/07.html#a457 Bpallen Technologies is also working on XFML support for their Teapot product: http://bpallen.com.

The real power of XFML lies in the concept of directly connecting topics. This allows authors to reuse existing indexing efforts. Metadata authoring applications that take advantage of this concept are being developed.

XFML Core was developed by Peter Van Dijck (http://petervandijck.net), with crucial support and feedback from Matt Mower, Travis Wilson, Eric Scheid, Danny Ayers, David Gammel, Leonard Will, Louis Argerich and many more.

July 06, 2002 XFML 0.2 released.

Version 0.2 of XFML is published today.
XFML is an XML format that lets you publish your metadata categories on the web in a standard format, and connect your metadata with metadata other people have published. This means you can automatically generated links to related content on your own and other websites.
Evolution of the language.

XFML version 0.2 introduces a number of refinements compard with version 0.1, most notably elements, which allow software to easily display singular or plural versions of topics, facets and occurrence types. (note - this was removed in the final spec.) The main outstanding issue currently being discussed is whether topics should be allowed to have multiple parents. It would mean more power, but we want to avoid increased complexity of implementation of XFML in a content management system. XFML is being designed so implementation of it in a content management system can be completed in, say, a weekend or two.

Compatibility with topic maps (XTM) and RDF.
XFML is being designed as a subset of the topicmap standard (http://topicmaps.org), optimized for a specific goal (sharing and connection faceted metadata between websites). Topic maps were designed so languages like this would be easy to define. XFML will be compatible with topicmaps in that any XFML file can be transformed into valid XTM easily. Work is also being done on RDF serialization of XFML, which will mean compatibility between XFML and RDF. This means that XFML authors will be able to use existing RDF and XTM tools.

May 30, 2002 XFML 0.1 published.

XFML version 0.1 is published by Peter Van Dijck (peter@poorbuthappy.com) at http://xfml.org. XFML is an open XML format for publishing and connecting faceted metadata between websites. It is based on topicmaps (http://topicmaps.org), and aims to achieve the ease of use of RSS.

© 2002, Peter Van Dijck. The XFML logo was designed by Bryan Bell.