Just how KH2 followed the special ending in KH1, BBS follows the secret ending from KH2.

I am guessing that KH3 is going to follow the secret ending in BBS.

No Nomura said think of BBS as a KH 0 because it's a really big game and KH I would be it's sequel.

And BBS will be the best KH since KH II not the Original.

It's part to the main story line but decide not to give it a number.

No, it's a prequel.  The game itself holds about as much importance in the KH universe as KH1 and KH2, such that it could've been called KH3.  But I'm guessing they called it BBS, because it wasn't on a console.  That's how I look at it anyways.

I'm one of the people of the people who preferred the original over the sequel, so this is good news to me.