Kim-Mai Cutler writes in TechCrunch how a radical UX focus was Instagram’s secret ingredient to success:
“With their UX skills, Krieger and Systrom refined Instagram to require as few actions as possible. Unlike the original version of Path, Instagram didnâ€™t force users to add tags about people or places to their photos. A photo could be posted in as few as three clicks. Mirroring Twitter, they made Instagram public by default.” […]
“All the while, Systrom kept saying he never felt threatened by Facebook. Facebookâ€™s mobile apps were just too complicated. The iOS app just had too many things in it. To please the companyâ€™s more than 850 million monthly active users, Facebook had to stuff every bell and whistle of the desktop site into its mobile app. That just wasnâ€™t conducive to a great user experience on a phone.
In contrast, Instagram kept its app lean. They didnâ€™t change much to the appâ€™s essential experience even as its user base ballooned. It was more important to say â€˜Noâ€™ to new features instead of â€˜Yes.â€™”