AniDB say that BMG is the sequel. Not the other way round. And it is definitely the prequel as the novel with the same name is also the prequel in the list of novels. Sequels are either with Tsubasa or her family but definitely with Arararararararagi's two sisters.
omfg HOW YOU GET HOW I DIDN'T KNOW ! OMG!!! IM SAD!
I use that anime countdown link in your sticky thread as they generally list anime earlier than AniDB, albeit with even less information than AniDB. But once I have found something interesting I check AniDB if they have an entry for it.
.... My eyes, they hurt. I was looking at some hentai tentacles too -- sorry >_>;;
As for Bakemonogatari, you know the last time I checked if they were going to have a prequel or a sequel to this was about a week and a half ago. I usually refresh my favorite anime on AniDB to see if there's going to be anything new. But on a serious note. I want more of Senjougahara - doubt there's going to be any serious scenes of her. We may get to see how things happened in her life, maybe .. ? I mean, a slight hope of her naked bo--seeing her again is great.
But we all know the majority of how it's going to start. That damn vampire little kid, Shinobo. I'm glad they're going to talk about Shinobo (was her name?) to see how she plays out.
Oh, one more thing
God, YOU BEAT ME TO IT AND IM SADDD! D:
At least we know it's coming. THE PREQUEL IS COMING!!!!