at the very beginning del.icio.us had a hierarchy operator: anything tagged "foo/bar" would internally also get the tag "foo" as well. i ended up pulling it out

at the very beginning del.icio.us had a hierarchy operator: anything tagged "foo/bar" would internally also get the tag "foo" as well. i ended up pulling it out. for finding untagged things, i had "system:untagged" automatically added if the items had no tags because mixing inner and outer joins was a nightmare in mysql.