1. A computing system for sending updated contact information, comprising: a display screen comprising a user interface that displays (i) identifying information of a sender associated with a client computer, (ii) existing contact information for an addressee extracted from an address book data structure of an address book of the client computer, and (iii) one or more response elements that permit the addressee to update the existing contact information; and an addressee computer hardware processor that, responsive to input from the addressee on the one or more response elements in the user interface, provides updated contact information of the addressee for transmission to the client computer, wherein the updated contact information of the addressee is transmitted to a computer server that subsequently transmits the updated contact information to the client computer.