Instagram is a mobile service application launched in October 2010 and created by Mike Krieger and Kevin Systrom.
It is available for Windows Phone, Android and iPhone users. It is basically a mobile photo sharing service where the users can click photos as well as create short videos for about 15-20 seconds and can share the same on all the popular social networking websites, Twitter, Facebook and Flickr.
Like other social networking services, Instagram too is a free service which can be used by people to follow others.
By July 2011, users uploaded 100 million+ photos and by April 2012, Instagram had 30 million+ registered users on Instagram.
But, in April 2012, Instagram was being sold for 1 billion dollars to Facebook.