Fallout MMO has been stuck in the middle of a legal battle for roughly half of forever, and it doesn't seem like the controversy is going to stop any time soon. Bethesda's most recent filing claimed that Interplay had only licensed the rights to use the Fallout name, rather than any of the other assets that would lead to developing an MMO. Interplay has responded to this claim by calling it outright absurd.
According to Interplay, the license between the companies specifically required Interplay to develop a Fallout MMO, using the name and all related assets as part of the overall experience. Using only the name and nothing else related to the franchise would be strictly against the terms of the original agreement. Although it's not clear at the moment how long this particular skirmish will take, it's obvious that both companies are still dedicated to fighting the rights out to the bitter end.