As the world becomes increasingly connected, the number of people we know and the ways we know them have exponentially increased. Organizationally this complicates things, and emotionally this requires more energy to navigate. Who am I losing touch with? Who does so-and-so know that I know?
Re-imagine the address book entirely. Connect in all the social networks you use to create a repository of everyone you know. Use residual social data to understand a number of intentions. Patterns of interaction indicate who's important and who you have or haven't been focusing attention on. Collectively enabling you to be a better friend.