sbarre has it right. You missed this part: "Instagram is the main mobile photo app."
Damn reading comprehension. ;)
To go a step further, consider: Flickr is available on every device (computer or phone) with an internet connection . Instagram was iOS-exclusive until a week or two ago, and yet it managed to reach sixty percent of Flickr's user base size. That's astounding.
I was addressing the part where it said "it's the photo app". It isn't "the" photo app. You can make the case that it's the most widely used mobile photo app after Facebook. But that != $1bn valuation or YouTube-like status.
Damn reading comprehension. ;)
To go a step further, consider: Flickr is available on every device (computer or phone) with an internet connection . Instagram was iOS-exclusive until a week or two ago, and yet it managed to reach sixty percent of Flickr's user base size. That's astounding.