Neustar is in the developmental stages of the worldโs largest, zip code based, local search engine portal.
Approximately 44,000 five digit numerical zip code values were retained by Neustar, the .US registrar for the development of this project.
Currently, if you type your zip code into a browser followed by the .US extension you will find geographically specific information for the surrounding area.
Today however, Neustar appears to be severely behind in their agreement with the US Department of Commerce, who they initially contracted with. The agreement calls for completion of the search engine by June of 2006
http://www.ntia.doc.gov/ntiahome/domainname/usca/usamend0015_10122005.pdf (Section 3, paragraph 3).
As one of the conditions to advertise on the zipcode.US search engine, businesses are required to have a .US extension for their website.
With the recent increase of .US sales, coupled with the
"hopefully" soon completion of the zipcode.US search engine, I think that the .US extension will not only gain in popularity, but surpass other ccTDLs. :gl: