I can't speak to its activity aside from the MUDstats numbers. When people who've come from there talk about it (You may talk about 'Blood of Dragons' on 'Game of Bones' though I do try to discourage bash-sessions about it unless you're doing so in private or on the channel that's reserved for being rude) the usual word goes that they either cannot get a scene, or the RP is repetitive nobles-having-huffs-at-other-nobles + tourneys, or that the player in question has been verbally abused by the staff there and cannot stand it any more.
Go to war, investigate magic, breed dragons, slay rogue dragons...
GoB is 1:1 in a time period that's kinda blank, but all of that is stuff we've done, or had people try with varying degrees of success, and a fair bit of fun. (Though the wars are mere skirmishes, and players do keep trying to tame the wild dragon just by yelling at it, which doesn't work, with comical results.)
@Alzie I think the confusion about BoD staff claiming that other games are not allowed to exist is because when Nymeria goes off on a rabid public howling spree about other games and how they are evil and bad and hurt her butt more than it has ever been hurt before, and are illegal and should be sued and she'd be in the right to do it, she actually means, "Hrmph, I wish people wouldn't do that," and when GRRM says, "Hrumph, I wish people would do that differently," he means that they are evil and bad and hurt his butt, etc.