You know your friends' email addresses and Twitter handles like the back of your hand. But in this day and age, it's easy to let your snail-mail Rolodex get woefully out-of-date. Here to help is Postable, a free new service that enables you to efficiently gather contact information.

The way it works is simple, not to mention ideal for the next time you send out holiday cards or party invites.

Upon signing up, you'll receive a short link to your Postable address book, which you then email to all your contacts. After clicking said link, they'll be prompted to fill out relevant info like mailing address, phone number and birthday. (Don't worry, they can't see one another's entries.) As each person enters his or her details, your digital Rolodex automatically populates. Pretty genius, right?

You can give others the link to send on your behalf (great for dividing and conquering with that guest list), export your data to an existing Gmail, Outlook or Apple address book and even print instant mailing labels from your personal printer.

Consider it your newest reason to patronize the U.S. Postal Service.

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