There isn't just one social graph, there are many. LinkedIn maintains your professional contacts, while Facebook has friends and family (and yes, often many professional). Twitter has some mix, as well, perhaps with a different filter. Aggregators take these disparate contacts and bring them into one place. A new service uses several APIs to merge them and give tools to better understand and utilize your network of contacts.
Who has time to fit exercise into their busy schedules these days? Or maybe there is time, but most of us simply lack the motivation to get up and do it. So what if there was an app that could give you that motivation? The Running Club app is a virtual running club that allows users to schedule live activities with friends in different locations.