Although Larry Page and Sergey Brin registered the google.com domain in 1997, Google wasn't officially launched till one year later, making Google 9 years old this year. Google's birthday has alweays been celebrated on September 27th with a doodle displayed on the homepage, and today is no exception.

"Google opened its doors in September 1998. The exact date when we celebrate our birthday has moved around over the years, depending on when people feel like having cake," says Google's help center.

You can read more about it directly from Google.