Google uses special logos (or doodles) to honor famous personalities, especially artists and scientists, on their birthdays. And they do something similar on your birthday as well.
{Spoiler Alert} If you visit the Google homepage on your birthday, you’ll find a special logo and when you hover the mouse over that logo, it will greet you with some personalized text.
It probably picks the date from your Google Profile and you’ll also need to be logged in to your Google Account to see that birthday logo. The feature has been around for an yearnow but if you jumped in late like me, do remember to visit google.com on your next birthday.
And here’s sample picture Google wishing a very happy birthday.