Just six months after reaching 500 million monthly active users, Instagram has topped the 600 million mark.
The Facebook-owned photo- and video-sharing network provided the following timeline illustrating its growth:

Oct. 6, 2010: Instagram founded
Dec. 21, 2010: 1 million users
Sept. 26, 2011: 10 million users
April 9, 2012: 30 million users
Nov. 6, 2012: 80 million users
Feb. 26, 2013: 100 million users
March 25, 2014: 200 million users
Dec. 10, 2014: 300 million users
Sept. 22, 2015: 400 million users
June 21, 2016: 500 million users
Dec. 15, 2016: 600 million users
Instagram said in a blog post:
A lot has changed this year, but the Instagram community and the diversity of expression it provides has remained consistent. And you now have more ways to share than ever before with Instagram Stories, live video and disappearing photos and videos in Direct. Additionally, with updated safety tools that give you more control over comments and other parts of your experience, we?re working to make Instagram safer than ever for connection and self-expression.
Readers: How soon will Instagram reach 700 million MAUs"

...