Signed up for the hell of it.
I imagine the only reason Beth hasn't pulled the plug yet is so they can attempt to recoup their investments from the initial wave of sales before they shut it down.
A successful MMO requires constant maintenance, and new content being developed; which means it needs to be coming from a stable, well-funded studio. Instead, it's coming from Interplay + Masthead, which isn't exactly what I'd call stable.
Masthead appears to have zero completed games under their belt, and are simultaneously developing "a post apocalyptic science fiction MMORPG set in the distant future." called Earthrise, along with the fallout MMO, which makes me wonder if they're sharing assets, in order to beef up what they're showing to Beth so it looks like they're actually getting work done.
Then we've got Interplay, which is a rotting corpse that has been hexed to life by Bethesda to <s>eat brains</s> make Fallouts, likely so that old fans who forgot what a clusterfucked piece of shit Interplay was will see the logo and think "Holy shit! A new Fallout game.. and it's from Interplay? Must be the real thing!". While the Fallout 3 generation will buy it either way because it's like Oblivion with guns.... but Online!
Hopefully I'm proven wrong, but I'm not getting my hopes up.