Instagram is a daily habit for more than half of the photo-sharing social network's users, co-founder Kevin Systrom said at a press event Thursday in New York.
He also noted that, in general, photos taken have more than quadrupled from 86 billion in 2000 to 360 billion in 2011.
The main event of the press conference was the unveiling of Instagram Direct messaging.
Ahead of the event, it was unclear just what the photo-sharing social network would announce, and speculation ranged from a photo-printing service -- based on the odd form of the invitations -- to a private messaging service that could rival Snapchat and WhatsApp.
Instagram has grown rapidly in the three years since it launched. With 150 million active users worldwide and its purchase by Facebook for $1 billion last year, it recently started running advertisements in an effort to bring in more revenue.