Plaxo

Plaxo helps keep people connected by solving the common and frustrating problem of out-of-date contact information. Users and their contacts store their information on Plaxo's servers. When a user edits their own information, the changes appear in the address books of all those who listed the user in their own address books. Because contacts are stored in a central location, it's possible to list connections between contacts and access the address book from anywhere.