

Simple Hierarchical Tagging - gnosis
http://inkblots.markwoodman.com/2006/02/01/simple-hierarchical-tagging/

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britta
A post from 2006? Anyway, a long time ago Delicious quietly implemented
experimental support of structured tags delimited by colons. You can tag
things "foo:bar" and "foo:baz" and then see all of those bookmarks by looking
at "system:has:foo". An example:
<http://www.delicious.com/britta/system:has:via>

Flickr uses colons too and calls these structured tags "machine tags":
<http://www.flickr.com/groups/api/discuss/72157594497877875/> \- if you're
interested in that kind of thing, Aaron Straup Cope is the person to read more
from: <http://www.aaronland.info/weblog/>

~~~
joshu
Those aren't really hierarchical That's more a way to pretend metadata is a
tag.

Way back, delicious.had hierarchical tags. If you tagged something as foo/bar,
it would be retrieved in a query for foo.

