Ask HN: What stats do you want to know about your address book?

Hacker News, we need your inspiration.<p>A little background: We are creating an address book management tool which aggregates all your contacts and makes them available to you on all your devices and services. This means we connect with phones, email and social networks, import those contacts, deduplicate the resulting complete address book and in turn export it back to wherever you could need it.<p>We are now in the process of making our product more interesting and more communicative. One of the ways we want to do this is by providing our users with extended statistics about their address book. Currently we tell them how many contacts they have, how many of them are linked to social networks and how many got updated within the last thirty days.<p>To extend upon this we are wondering:<p>- What are things you always wanted to know about your address book?<p>- What are things about your address book that would be helpful to know?<p>- What are stats that would make you chuckle?<p>- etc.<p>Thanks!