What was once an iPhone-only social network has quickly become one of the world’s largest social behemoths. Instagram’s co-founder, Kevin Systrom, announced today that the photo-sharing network just surpassed the 100 million active users mark.
Compared to its parent company Facebook, 100 million active users doesn’t sound like much. But when you consider that Twitter just hit the 200 million active users mark last year, Instagram’s got something to be proud of because it’s a much younger service.


