It’s not like these aren’t documented, but I keep forgetting where.
WOEID place types:
$woetype = array(
'7' => 'town',
'8' => 'state-province',
'9' => 'county-parish',
'10' => 'district-ward',
'11' => 'postcode',
'12' => 'country',
'19' => 'region',
'22' => 'neighborhood-suburb',
'24' => 'colloquial',
'29' => 'continent',
'31' => 'timezone',
);
They can be queried via YQL:
<?xml version="1.0" encoding="UTF-8"?>
<placeTypes xmlns="http://where.yahooapis.com/v1/schema.rng" xmlns:yahoo="http://www.yahooapis.com/v1/base.rng" yahoo:start="0" yahoo:count="1" yahoo:total="1">
<placeType yahoo:uri="http://where.yahooapis.com/v1/placetype/35" xml:lang="en-us">
<placeTypeName code="35">Historical Town</placeTypeName>
<placeTypeDescription>A historical populated settlement that is no longer known by its original name</placeTypeDescription>
</placeType>
</placeTypes>