One of the social media success stories of 2011 was easily the photo-sharing app Instagram.   Despite only running on Apple ‘iDevices’, Instagram boss Kevin Systrom reckoned he had 16+ million users at Christmas.

Post Christmas sign-ups combined with Apple naming Instagram app of the year means that total is probably not far off 20 million by now.  And the company estimates that the Android version finally in the works will result in the numbers doubling. Read more »