Instagram was founded by Kevin Systrom and Michael Krieger in October 2010. It was later acquired by Facebook in April 2012. The app lets users upload media that can be filtered and organized by hashtags, geographical tags, and categories. You can share posts publicly or privately with approved followers. Users can browse other users’ content by tags and locations, view trending content, and like photos. They can also follow other users to add content from them to a personal feed.
Instagram was initially distinguished by allowing content to only be displayed in a square (1 to 1) aspect ratio of 640 pixels wide to match the iPhone screen size at the time. By 2015, these restrictions were lifted with an increase to 1080p. It also added messaging capabilities, the ability to include several images or videos in a post and a Stories feature which allows users to post their content sequentially, with each post accessible for 24 hours. By January 2019, Stories was used by 500 million people per day.