Typically, within the Universe of 69 Worlds, all of the worlds together form a "universal village" in which the inhabitants are aware of the other worlds and regularly interact with each other
An isolated world is a world that has yet to be opnely visited by the denizens of the universal community; they are basically just like Earth in that the inhabitants are completely unaware of the existence of extraterrestial life and the surrounding events.
Isolated worlds are protected from outsiders by a select few and governments throughout the Universe have declared it illgal to enter them without permission, for the mental health of these worlds' inhabitants. As such, they are out of the high-speed loop of information and culture of the connected Universe, and do not enjoy nor need to service of browsers such as Firefoxes.
Isolated worlds have not yet been visited by Smoosh.