More than six years after its debut, Instagram remains the archetypal example of an app that was a phenomenon the moment it hit the App Store. The proposition it offered–simple, elegant photo sharing, with fun creative tools–kept on accumulating new fans at such a clip that you can understand why the company was hesitant to mess with its formula, even after it became part of Facebook in 2012. Recently, however, Instagram has done a whole lot of evolving, and it’s done it in rapid-fire fashion. Most notably, the company integrated something nearly identical to the concept of Snapchat’s “Stories” mini-multimedia shows into its own app, and then built it out with features such as live video streaming. The idea was so immediately popular inside Instagram that it changed the app in a way that’s rare for any one feature to do. Read more at Fast Company.