It's big events that "make" web companies. Twitter wasn't taken seriously until people started breaking news on it and now it was Instagram's turn. Instagram is not exactly the first thing that comes to mind when you think of the future of news, even "citizen" or crowdsourced news.
But during Hurricane Sandy, it was Instagram that drew people to it and it was there that they posted updates, in the form of photos.
In fact, by the time it was through, Instagram had amassed 800,000 photos tagged with #Sandy or something similar. Compare this to the previous big event, the Super Bowl with 85,000 photos.
Granted, of the 800,000 photos, many were just people in their homes hunkering down for the storm.
And half were probably of the same photoshopped shark swimming in New Jersey. That's not an official figure, but it could be accurate.