Instagram has rocketed past the 400 million user mark, with more than 80 million pictures shared daily at the Facebook-owned service.
The number of people sharing pictures and videos each month using Instagram soared from 300 million at the start of this year and tops the number of people using Twitter monthly by nearly 100 million.
"While milestones like this are important, what really excites us is the way that visual communication makes the world feel a little bit smaller to every one of us," Instagram said in a blog post.
"Instagrammers continue to capture incredible photos and videos from all corners of the Earth (and even the solar system)."
More than half of the last 100 million people to join Instagram live in Europe or Asia, with Brazil, Japan, and Indonesia seeing the strongest growth, according to the service.
The list of high-profile new Instagram users who quickly won legions of followers included David Beckham, Caitlyn Jenner and footballer Toni Kroos.
Earlier this month, Instagram unveiled plans to expand its offerings to advertisers, opening up possibilities for global marketing efforts on the photo-sharing network.
The expansion is intended to allow advertisers to launch global campaigns in a variety of formats including video ads of up to 30 seconds.
Instagram, which was acquired by Facebook in 2012, has had only limited advertising opportunities up to now.