Why does the ranking of countries in olympic medal tally when US does the tallying?

Question

Can anyone explain why a US company like yahoo reports ranking differently only in US? Is it because only in US the standard is different?

The following countries report the medal tally in the same way as IOC (International Olympics Committee) reports it.

ABC Australia

http://www.abc.net.au/olympics/

British Broadcasting Corp (BBC)

http://www.bbc.co.uk/

Yahoo France

http://fr.sports.yahoo.com/jeux-olympiques/2008/medailles/

Yahoo australia

http://au.sports.yahoo.com/olympics/

Germany

http://de.eurosport.yahoo.com/olympische-spiele/

But yahoo US reports that USA topped the list going by total number of medals won. Is that a standard with in US only? (standard set by US olympic committe ???)