+Extracted from the B<year> or B<DATE> tag. If not found defaults to
+B<year/UNKNOWN>.
+
+=item B<decade>
+
+Also extracted from the B<year> or B<DATE> tag. If not found
+defaults to B<decade/UNKNOWN>.
+
+=item B<v1genre>
+
+If a mp3 file has an ID3V1.1 genre tag, its value is assigned to
+v1genre.
+
+=item B<audiotype>
+
+Type of audio file (mp3, ogg, flac). Always set.
+
+=back
+
+=head2 Special Directories
+
+=over 4
+
+=item B<TRACKS>
+
+All tracks that match the given tag expression, whether they have an
+assigned artist and album or not.
+
+=item B<NOARTIST>
+
+Tracks matching the given expression that do not have an artist tag.
+
+=item B<NOALBUM>
+
+Tracks matching the given expression that do not have an album tag.
+
+=item B<ALL>
+
+This is a special directory in the root of the filesystem, that
+provides access to all the indexed files, regardless of tags assigned.
+
+=back
+
+=head1 FUSE AND MOUNTING AUTOMATICALLY
+
+For others to be able to view your id3fs mount(s), you need to set the
+option B<user_allow_other> in F</etc/fuse.conf>.
+
+To mount a filesystem automatically, put an entry in F</etc/fstab>
+like:
+
+ id3fsd#/source/dir /mount/point defaults 0 0
+
+=head1 CAVEATS
+
+Because id3fs offers a combinatorial explosion of views of your files,
+processes recursing into the mount point will take a B<long> time to
+traverse it.
+
+Ensure your backups, cron jobs, F</etc/updatedb.conf>, etc. are
+configured to exclude the mount point.