Facebook took 4 years to reach 100 million users. Instagram debuted in October 2010 and had 1 million users by 2 months and 10 million by September 2011. With approximately half a billion Android users around the globe, there is much more upside ahead for Instagram which is why it was worth all of that money to Facebook.
After Instagram release on Android Instagram gains 10 Million customers till now and is increasing at very fast pace. Downloads also pacified due to Facebook going to buy the company. Rakshith, the creator of gramfeed, pinged us this morning after noticing the milestone from Instagram’s API. The 40 millionth user is valentinoelbuti. It seems at the time of this post’s writing, Instagram has exactly 40,026,379 users — or rather, roughly 5% of Facebook’s active user base.