As a vBulletin user I do laugh when I get e-mails about their blogging service. You follow the links, and read the basic details - Use our blogging service, only $50!
Yep, because I'm going to pay $50 for something which I can get from a recognised blogging platform like Wordpress for nothing.
I don't care how community orientated it might be, given the choice I'll take the option of the expert in the field. Plus the price is better, always a benefit.
Hmm, makes me wonder why I paid for vBulletin for forums when there are free alternatives? Years of familiarity with the product and a trusted reputation, which sounds an awful lot like many people's experience with Wordpress, only without any payment.
It seems to me like vBulletin are stretching themselves for more income here. What's more while they work on blogging their users' most repeated request seems to be for a vB CMS, which would make a lot more sense. But why let that stand in the way of the bottom line?