Which came first, Harry Potter or Twitter?

Harry Potter came first, by 9 years. Harry Potter and the Philosopher's Stone was published in the UK.

Side by side

Harry Potter

Bloomsbury published the first book in June 1997 with a print run of 500 copies, most of which went to libraries, after twelve other publishers had rejected the manuscript. The company's chairman gave the first chapter to his eight-year-old daughter, who demanded the rest. It came out the same year as Netflix was founded and a year before Google.

Twitter

The first tweet — "just setting up my twttr" — went out on 21 March 2006, and the service opened publicly that July. The 140-character limit came from SMS: a text message allows 160 characters and 20 were reserved for the username. When the limit doubled to 280 in 2017 the SMS constraint had been irrelevant for years.