Why Affiliate program networks pay more for US person ?

[indieover]

i think thats because most of webmasters are also from us so its easy for them to pay us members

But people from outside of US are willing to work for less money also but why they target only those members ??

well good question. i think it does not really matter how much the people will ask for those affiliate marketing. they just believe that it is more profitable for them to concentrate on USA though they will pay more and that they will be rewarded more with those members in USA.