but .us has many handicaps in its domestic market that are unique to .us because of historical reasons
1) .gov and .mil. Official US federal sites use .gov and .mil, yet for virtually every other country in the world offical goverment sites end in the country TLD. It get even worse the US state goverment sites are moving away from .us to .gov. If .gov and .mil were replaced with .gov.us and .mil.us then .us will get a big boost. Will this happen I seriously doubt it.
2) .edu. Again while US Universities use .edu Universities in other parts of the world for the most part do not. They tipically use the country TLD.
3) Large famous us based multinational brands. For the most part they use .com for the US site and the corresponding country code elsewhere. In Canada they brand for the most part .ca, in the us .com.
My take is that .us will not reach the level of domestic market penetration of .ca or .co.uk in a long time. At this point .us seems dominated by speculators and trademark protection. The one redeeming factor for .us is the size of the domestic market. So a 5% pentration of the US market by .us would put .us on a par with .ca (if we assume the latter has a 50% penetration in Canada). To reach the level of .co.uk .us would need about 15% of the US market etc.
The best hope for .us is for americans to actually use their national TLD. But as things stand...
www.navy.us is a lame link and so is
www.navy.mil.us
The official US navy site is at
www.navy.mil
I rest may case