Instagram is a free photo sharing application that allows users to take a photo, apply a digital filter to it, and then share it on a variety of social networkingservices, including Instagram's own. A distinctive feature confines photos into a square shape, in homage to both the Kodak Instamatic and Polaroidcameras. This contrasts with the 4:3 aspect ratio more typically used by mobile device cameras.


Facebook to acquire photo-sharing app Instagram for $1 billion