Short answers, pulled from the story.
Instagram launched on the 12th of October 2010 with a strict requirement that every photo must be a perfect square. This 1:1 aspect ratio was a technical necessity designed to match the width of the iPhone screen at the time.
Kevin Systrom and Mike Krieger created Instagram from a failed check-in prototype called Burbn. Facebook acquired the company on the 6th of September 2012 for approximately one billion dollars in cash and stock.
Instagram launched the Stories feature on the 8th of August 2016 as a direct response to Snapchat. By the 24th of June 2018, 500 million people used Stories daily.
Instagram changed its feed from chronological to algorithmic on the 4th of April 2016. This decision led to significant negative feedback and concerns about mental health and the spread of misinformation.
The Wall Street Journal published internal research on the 14th of September 2021 revealing that Instagram worsened poor body image among young people. The study found that 13% of British and 6% of American teen users with suicidal thoughts could trace them to Instagram use.
Instagram launched Reels on the 5th of August 2020 to compete with TikTok. The feature allowed users to create vertical videos less than 90 seconds of duration.