Presented in a concise problem-solving manner, so I don't waste your valuable time.<p>Subproblem 1:<p>People still have to enter all details about their personal contacts (e.g. address, phone numbers, e-mail accounts, birthday, …) manually in their address book, phone, computer, ... This is quite a tedious task. There should be an easier way to do this.<p>Subproblem 2:<p>The details about your personal contacts are never up to date. If someones moves, changes their phone number or e-mail, … they have to inform everyone they know through e-mail, SMS, Facebook, ... Some people get neglected, which is human, but sucks. Facebook, Twitter and LinkedIn only partially solve this problem. The information you share with these services is never complete. I, for example, only share my name, e-mail and birthday with my FB, twitter and LinkedIn contacts.<p>Solution:<p>A small social network where a user enters his full contact details and shares it with the people he chooses (kinda like Facebook where people can add you as a friend). He can request other people to have their information shared with him (Facebook: add people as a friend). The contacts are stored in the cloud. That way they can easily be synced across several devices (phone, computer, …). Whenever a user moves to a new place, gets a new phone number, … he just has to update his account on the website. All of his contacts (Facebook: friends) will automatically receive the new information, so their address book is always up to date.<p>Btw, Plaxo is not the way to go. It's really not user-friendly.<p>tl;dr:<p>Problem: Enter contact details manually.<p>Solution: Just add the contact to your network.<p>Problem: Address book never up to date.<p>Solution: Enter the new information once, everyone's address books gets updated.<p>Problem: Address book not always available.<p>Solution: Synced across multiple devices through the cloud.<p>Thank you for your time. I really appreciate it!