Mike Krieger and Kevin Systrom created Instagram in October of 2010.  Krieger and Systrom created the app after being inspired by their shared love of technology and photography.  Their app was an immediate success gaining millions of users in a few short years.  One of the main reasons that they decided to create Instagram in the first place instead of using one of the myriads of other image sharing websites such as Facebook and Twitter, is because they felt that these other websites did not allow people to share images meaningfully, so they decided to create their own alternative.  Another reason why Instagram got so popular was because they managed to release their app right when social media was becoming popular and when more people started getting access to faster broadband internet.  As time has gone on the app has continued to add features that not only keep the current users of Instagram happy, but also bring in new users to the app everyday

What I think makes Mike Krieger and Kevin Systrom exemplary entrepreneurs is the fact that they found a common passion in an underserved market, so they created their own app to fill the void.