Instagram surpasses 400 million users

Instagram hit their 300 million user milestone late last year, but they've added a huge 100 million users in the last 9 months to reach 400 million users in total now.

The photo-focused social network is an interesting beast, especially under the wing of Facebook. Instagram has noted that 75% of these active users are coming from outside of the United States, but can it continue this huge growth? Facebook acquired Instagram back in 2012 for $1 billion, but that deal feels like nothing when you consider the social network slapped down $19 billion to acquire WhatsApp in 2013.