Quite a crop of languages or extensions to existing languages has popped up lately. Many of these languages are related to content aggregation; others, such as XFN, are used to tag relationships between people and people.
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XFN is the acronym for XHTML Friends Network. Developed by Matthew Mullenweg (who also is the developer of the semantic blogging software WordPress) along with standards evangelists Eric Meyer and Tantek Çelik, XFN is conceptually like other aggregation technologies, except it uses HTML vocabulary, not other markup languages.
Mullenweg looks to the simplicity of XFN as one of its most appealing points.
I think there are a couple of really exciting things about XFN,
he
says. It leverages higher-level semantics into the HTML everyone already
knows. You don't have to learn a new awkward syntax or mess with strange
files. It takes what you're already doing, linking, and enriches it
semantically.
By adding a number of attribute values to the rel attribute, anyone writing documents in HTML or XHTML can make their links XFN-friendly.
Here's an example of a link on one of my site's pages to Biz
Stone's web site:
<a href="http://www.bizstone.com/"
title="Go to http://www.bizstone.com"
rel="friend colleague">Biz Stone</a>.As you can see, I added the rel attribute to the link and also added values that describe our relationship as being friends and colleagues. Beyond simple, but sure to be very effective when blogrolls, specialty search engines, blogging tools, and markup editors begin supporting XFN more explicitly.
The other piece of XFN that Mullenweg points to as having tremendous
potential is that XFN is distributed, unlike social networking web sites.
XFN doesn't tie you in to any one place; it connects people across
domains, literally,
Mullenweg says. The history of the Web has shown
that decentralization is the wave of the future.
Learn all about XFN on the XHTML Friends Network site.
For Web loggers, XFN — the XHTML Friends Network — enables coding links to other bloggers with a "rel" (relationship) tag. With enough participation, tagging eventually can permit virtual friendship-building.