Would you use it: A new address book?

I've been thinking about a problem I had for quite a while now: Contact information that are out of date from people that I haven't talked to in a while or are missing altogether (like postal addresses) because I didn't add them.

Here is the core idea:

An app that works as a better address book but can automatically inform your friends or certain groups whenever you change your profile (job, address, phone number, website, important milestones etc.). The app will automatically push the update to their address books or send them a notification when they don't have the app installed. The same will happen, when they update their own information.

Would you use it?