Sharing your metadata with XFML
XFML is a language that lets websites talk to each other about their metadata. It’s not a CMS, but a framework for one. It appears to be a simplified version of topicmaps.
An example given on the website explains how to set up your system to “[...] automatically generate links to stories about the same topics on your friends weblog that show up with your stories.”
November 8th, 2002 at 20:12
XFML Core or version 1.0 has been released since. Check http://xfml.org for the spec and a list of compatible software