https://www.cnet.com/news/google-marks-20-years-of-doodling-with-20-notable-doodles/

Since then, the idea of adding colorful graphics to Google's logo to highlight notable people, events, holidays and anniversaries has taken off, spawning its own following among web users. They've celebrated Pac-Man's anniversary, Copernicus' birthday, Mother's Day and the World Cup, as well as reminding us of lesser-known real-world heroes.

"When doodles were first created, nobody had anticipated how popular and integral they would become to the Google search experience," a corporate history of the Doodle recalls. "Nowadays, many users excitedly anticipate the release of each new doodle and some even collect them."