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.
Connected, which happens to be today's Mashup of the Day has options to connect to Facebook, Google Calendar, Google Contacts, Google Gmail OAuth, LinkedIn and Twitter. But unlike simple aggregators that re-publish your many streams in one place, Connected becomes a useful place to visualize and interact with all your contacts. Even better, you can sort by the date of your last conversation, whether it was an email, Facebook message, LinkedIn correspondence or Twitter thread.
Its developers think they're on to something, too. The service, which also lets you annotate and edit your contacts, costs $9.99 per month, but there's a 14 day free trial.
Aggregators like Connected are going to need to provide these sorts of advanced and useful services to stick out from what anyone could whip up in a few hours. The social APIs are powerful on their own, but the cross-company tools that provide something new from a combination of the graphs is where we'll find the really great stuff.