techcrunch.com — When you think Twitter, you may think realtime news, or CRM, or brand marketing, or maybe even Justin Bieber, but "eCommerce"? Probably not. In the social network landscape, Facebook is generally seen as being the most eCommerce-inclined, what with its "F-Commerce," but up to this point, consumers really haven't fallen in love with the idea of brands replicating their storefronts on Facebook .