Facebook-owned Instagram hit the 400 million mark today. The photo-sharing sharing app posted a celebratory picture and stated that the 400 million strong user base has about 75 percent living outside the US.

“Among the last 100 million to join, more than half live in Europe and Asia. The countries that added the most Instagrammers include Brazil, Japan and Indonesia”

The new 100 million users helped Instagram race ahead of twitter, which is currently at 316 million active monthly users.  Facebook is surely reaping from the benefits from buying Instagram for $1 billion in 2012 now that Instagram has also taken to advertising. Research firm eMarketer [...]