You could interpret this as the Canadian ereader entering the US fray, given Indigo retaining a 51% controlling share.
It's a pretty impressive offering. An e-ink reader. A great price point ($99). Wifi. A store. Good pricing and decent selection in the store. Reasonable format selection (ePUB, PDF and Adobe DRM) allowing buyers to get library books. Apps on other mobile devices and tablets available at launch. Presence in brick-and-mortar stores so you can try before you buy. Some kind of nod to social networking.
I suppose one of the goals of this promotion would be to reassure anyone who bought a Kobo ereader through Borders that the Borders BK should not make them fear their ereader.
At least one of the Amazon reviews for the Kobo (3rd party seller listing) claimed to have bought it for under $60 at a Borders going out of business sale.