http://www.buildyourforum.com/about83.html

biz 300 posts -300 posts/yr to renew
bz 500 posts - 500 posts/yr to renew
ca 400 posts - 400 posts/yr to renew
cc 500 posts - 500 posts/yr to renew
cn 500 posts - 500 posts/yr to renew
com 300 posts - 300 posts/yr to renew
com.cn 500 posts - 500 posts/yr to renew
de 450 posts - 450 posts/yr to renew
in 450 posts - 450 posts/yr to renew
info 230 posts - 230 posts/yr to renew
net 300 posts - 300 posts/yr to renew
net.cn 500 posts - 500 posts/yr to renew
nu 300 posts - 300 posts/yr to renew
org 300 posts - 300 posts/yr to renew
org.cn 500 posts - 500 posts/yr to renew
tv 700 posts - 700 posts/yr to renew
us 300 posts - 300 posts/yr to renew
ws 500 posts - 500 posts/yr to renew

需要发大量的帖子，英语好的可以去44看