WOEID

A WOEID (Where on Earth IDentifier) is a unique reference identifier assigned by Yahoo! to identify any feature on Earth.

External links

http://developer.yahoo.com/geo/geoplanet/guide/concepts.html

http://geobloggers.com/2008/05/12/yahoo-woe-where-on-earth-that-is-ids/

http://engineering.twitter.com/2010/02/woeids-in-twitters-trends.html