Not sure I understand what you are asking.

www.xxx.mobi - .mobi is a top level domain approved by ICANN on July 11 2005
dedicated to delivering the net to mobile devices. .mobi was made available to
the public in 2006.

Its neither part of firefox or ubuntu. Though you would use Firefox to get to a
.mobi domain.

i listen 2 talkstreamlive. when i use ms with ie7 i cant play .mobi stream. with
ubuntu & ff, all works well. question is why cant ms play my streaming?