Xobni co-founder Matt Brezina is launching a fun and clever product today to let iPhone users send real, physical postcards directly from your iPhone (or from the Web). Postagram is the app. Sincerely is the new company he started to create it.
Postagram uses the Instagram API. It requires that users have an Instagram login and the app installed on their phone. But from there, it looks like a quick procedure to select a photo from your Instagram library, put a message of up to 140 characters on it, address it (unfortunately the app can’t access your phone’s address book directly), and have it sent out as a postcard through the mail.