Short Version:
Good - The ability to fire online purchases directly over to your Facebook page may seem weird to non-facebookers. But for those on the site, you understand how much you keep up on peoples' lives via their status and whatever they super-poked you with today. Allowing me to, upon checkout of buying my new Flat screen TV, click a button to instantly show off my new toy to my friends seems really appealing. And as a marketer, I relish the opportunity to have this more authentic way for consumers to brag about their purchase of my brand.
Bad - Challenge could be the online only nature of the app. With a good number of purchases researched online but still bought in the real world, how can this app be expanded to be more inclusive of broader shopping behaviors? Seems like the addition of a "considering" feature could be a useful plus-up. For example, if a user is on bestbuy.com looking at flat screen TVs, maybe they can add categories or specific products to their considerations. For users this could be a useful tool to gather intelligence from a network of friends.
Can't wait to see what else they announce.