Instagram is a free photo sharing application that allows users to take photos, apply a filter, and share it on the service or a variety of other social networking services, including Facebook, Twitter, Foursquare, Tumblr, Flickr, and Posterous. The application is compatible with iPhone, iPad or iPod Touch or Android devices running Android.
In an homage to both the Kodak Instamatic and Polaroid cameras, Instagram confines photos into a square shape. This is in contrast to the 3:2 aspect ratio normally used by the iOS device cameras.
In April 2012, Instagram was acquired by Facebook.