Kevin Systrom and Mike Krieger launched Instagram in 2010 as a photo-sharing mobile app.
Before Instagram, Systrom and Krieger worked on Burbn, a location-based check-in application. They narrowed the idea to its strongest feature—mobile photo sharing—and released Instagram for Apple's iOS in October 2010. The service became known for square photos and built-in filters, although it later supported broader formats and video.
Facebook announced its agreement to acquire Instagram in 2012 for approximately $1 billion in cash and stock. The acquisition did not mean Instagram was originally a Facebook product; it was founded independently. Instagram's early focus on a small set of mobile features is often cited as an example of narrowing a startup's product to achieve traction.