Short answers, pulled from the story.
Steve Huffman and Alexis Ohanian launched Reddit in June 2005 as two University of Virginia roommates. They initially pitched a food ordering service called My Mobile Menu to Paul Graham's Y Combinator incubator before receiving acceptance for the new idea Graham called the front page of the Internet.
Aaron Swartz joined the Reddit team in November 2005 and rewrote the site's software from Common Lisp to Python using a framework he developed called web.py. His work shifted the site toward simplicity and maintainability to allow it to scale, though he was fired in January 2007 following a blog post criticizing the corporate environment at Condé Nast.
Steve Huffman returned to Reddit in 2014 and 2015 to take the role of CEO and executive chairman respectively. He led a major redesign in April 2018 that introduced a hamburger menu, new fonts, and a mobile-first approach while banning several offensive and sexual communities.
Reddit experienced a series of blackouts in July 2015 where moderators set popular subreddits to private in protest of the firing of Victoria Taylor. This event led to a Change.org petition to remove CEO Ellen Pao which reached over 200,000 signatures before she resigned on the 10th of July 2015.
Reddit played a significant role in political activism through events like the March for Science and the GameStop short squeeze organized on the subreddit r/wallstreetbets in January 2021. The site also facilitated charitable efforts including raising more than $100,000 for comedians Jon Stewart's and Stephen Colbert's Rally to Restore Sanity and/or Fear and more than $180,000 for Haiti earthquake relief efforts.
Reddit debuted on the stock market on the morning of the 21st of March 2024 with the ticker symbol RDDT and an opening price of $34 per share. The company reached a market cap of $9.5 billion by market close on their first day of trading after a $410 million funding round valued the company at more than $10 billion.