We often find contact information in the body or signature of an email, but we neglect to add it to our contacts and are forced to search our emails for a phone number or address later on. Morse takes care of that problem by pulling contact information stored in your emails and adding them to your address book automatically.
Morse only requires that you have a Gmail account. You simply sign up for the beta by authorising access to your Gmail account, and then Morse gets to work. The first full scan can take a while, especially if you have a bunch of emails, but you'll receive a notification in your inbox once complete. It will provide instructions on how you can keep your new, updated address book in sync with your mobile devices too.
Otherwise, Morse is a mostly hands-off service. It caught me off-guard at first because you don't see anything happening, but be assured that the web app is working behind the scenes. Morse keeps the date and the sender/receiver information so it can track matches, but beyond that there is no need to retain more of your information.
Morse is currently in beta and free to use. Just sign up, let it do it's thing, and end up with a more comprehensive address book when it's finished.