Yeah I was confused by this too. The other main automotive forum Im on, Mischief.tv, works on Tapatalk, and they are running on vBulletin 4.0.7
I would love this, I dont have an iPhone, but I do have an iPad, and yes, I know I could just use Safari, but its so slow on the iPad. Tapatalk makes forum surfing so much faster, especially when Im away from home.
And I'm sorry, but the Bimmerpost iPhone app just doesnt work all that well.