Around the country, hospitals and doctors are forming Accountable Care Organizations, where providers team up to better manage patients. This year, we're watching Camden, N.J., as the new health law takes hold, part of a series we call Diagnosis: Camden. Also, the online food delivery service - GrubHub - begins trading on the New York Stock Exchange. The company could raise around $176 million. In fact, the pre-IPO price has moved higher over the past few months, even before it started trading on Wall Street. Why is it so attractive to investors?