The words "Harry Potter" turn red in Facebook updates, and when you click on them an animated wand appears. As fans quickly discovered, the effect also works with the names the Hogwarts Houses, with each turning their respective colors.
The Facebook fun comes 20 years to the day after Harry Potter and the Philosopher's Stone was published in the United Kingdom. On Twitter, the anniversary was celebrated with a custom emoji.
20 years ago today a world that I had lived in alone was suddenly open to others. It's been wonderful. Thank you.#HarryPotter20— J.K. Rowling (@jk_rowling) June 26, 2017