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 didn’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. Facebook’s mobile apps were just too complicated. The iOS app just had too many things in it. To please the company’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 wasn’t conducive to a great user experience on a phone.
In contrast, Instagram kept its app lean. They didn’t change much to the app’s essential experience even as its user base ballooned. It was more important to say ‘No’ to new features instead of ‘Yes.’”