With a looming $10 billion IPO on the horizon and a community that’s estimated to hit 1 billion users this Fall, Facebook seems unstoppable. Yet on one important front, the store front that is, Facebook has exposed an imperfection. People are not proving ready to actually buy goods and services in Facebook – at least not at the scale retailers are used to seeing through traditional e-commerce. And suddenly, many question the role Facebook actually plays in the monetization strategy…