Google is celebrating its birthday - with digital cake.

The search giant filed for incorporation on September 4, 1998, but according to Wired they celebrate their birthday "whenever we feel like cake".

This year Google has unveiled an animated cake Google Doodle on its homepage to mark the occasion.

The cake has its candles lit, before being eaten away to reveal the Google logo. Very sweet.

Here are our 14 favourite Google facts:

  1. Google's original name was 'BackRub'
  2. The BackRub search engine is still accessible - but isn't working. "Many services are unavailable due to a local network faliure beyond our control. We are working to fix the problem and hope to be back up soon," says a message posted on the page in 1997.
  3. Backrub was hosted on ten 4GB hard drives in a storage case made of Lego
  4. 15% of Google's daily searches have never been typed in before
  5. 'Google' is a play on the word "googol", a term meaning a number 1 followed by 100 zeros
  6. Google's first company dog was called Yoshka
  7. In 2000, Google announced MentalPlex, a way to read your mind for search results. It was a joke.
  8. Google handles 100 billion searches per month
  9. ...and has 100 million active users of Google Plus
  10. Klingon has been an official language of Google since 2002
  11. The first Google Doodle was posted in 1998, to let people know that founders Sergey Brin and Larry Page were at the Burning Man festival
  12. 'Google' became a verb in the Oxford English Dictionary in June 2006
  13. Google estimates more than one million spam pages are created each hour
  14. Google.com was registered in 1997 - a year before the site launched
CLICK through the slideshow for a selection of the Google Doodlers' favorite doodles:
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  • Ryan Germick, Doodle Team Lead

    Favorite Doodle: <a href="http://www.google.com/doodles/robert-moogs-78th-birthday" target="_hplink">Moog synthesizer</a> (interactive) Occasion: Robert Moog's 78th birthday "We've been playing with the Google Doodles for years, so it's seems fitting to let users play too. It was really fun geeking out with engineers to celebrate a patron saint of the nerdy arts."

  • Jennifer Hom, Doodler

    Favorite Doodle: <a href="http://www.google.com/doodles/freddie-mercurys-65th-birthday" target="_hplink">Freddie Mercury animation</a> Occasion: Freddie Mercury's 65th birthday "I loved the opportunity to work with all the other doodlers, other animators within Google and Queen's manager to develop this video. It also didn't hurt that I was able to listen to the same 90 seconds of 'Don't Stop Me Now' and still love the song afterward."

  • Mike Dutton, Doodler

    Favorite Doodle: <a href="http://www.google.com/doodles/79th-anniversary-of-the-first-drive-in-movie" target="_hplink">Drive-in Theater</a> Occasion: 79th anniversary of the first drive-in movie "While I really enjoyed working on the Anniversary of the Drive-In Theater, I'd have to say the user reaction is what makes this my favorite doodle. It inspired a great sense of nostalgia as users shared on various social networks their own personal experiences, some even being nearly-forgotten childhood memories. We may have taken them to the show, but in the end, they were the stars."

  • Sophia Foster-Dimino, Doodler

    Favorite Doodle: <a href="http://www.google.com/doodles/60th-anniversary-of-stanislaw-lems-first-publication" target="_hplink">The Cyberiad</a> Occasion: 60th anniversary of Stanislaw Lem's first publication, "The Astronauts" "One of my favorite aspects of working as a doodler is that I can often find projects that are an intersection of my various interests. In the case of this doodle, celebrating the first publication of esteemed Polish sci-fi author Stanisław Lem, I was able to combine my love for science fiction, video games, and pen & ink illustration to create a complex interactive world featuring characters from one of Lem's most beloved works, The Cyberiad."

  • Willie Real, Doodler

    Favorite Doodle: <a href="http://www.google.com/doodles/grandparents-day-2012" target="_hplink">Polish grandparents</a> Occasion: Grandparents Day 2012 "This doodle is one of my favorites because it captures a sentimental moment between proud grandparents and their grandchildren. Out for a slow stroll in the park, the grandparents make sure the children are bundled up, and in turn the little guy holding hands with grandpa imitates him by carrying his own 'walking stick' while grandma holds on to her little 'pierogi'. A good friend of mine is Polish and I've visited him twice, where his folks -- real Polish grandparents -- have welcomed me with the utmost hospitality."

  • Kris Hom, Engineer

    Favorite Doodle: <a href="http://www.google.com/doodles/google-instant-launch" target="_hplink">Particles</a> Occasion: Google Instant launch "My favorite because it resulted from a collaboration of Google engineers from many different backgrounds. I still love to play with this because it's both fun and calming. It lives on in the header of the official Google Blog at http://googleblog.blogspot.com/"

  • Corrie Scalisi, Engineer

    Favorite Doodle: <a href="http://www.google.com/doodles/louis-brailles-107th-birthday" target="_hplink">Braille Google</a> Occasion: Louis Braille's 107th birthday "This one ran before I even joined the company so I have no idea who made it. There's a wonderfully fun simplicity to it. I remember seeing it when it ran and thinking that it was amazing how clearly recognizable the logo was, even without recognizable letters."

  • Marcin Wichary, Engineer

    Favorite Doodle: <a href="http://www.google.com/doodles/st-georges-day-the-30th-anniversary-of-the-zx-spectrum" target="_hplink">ZX St. George</a> Occasion: St. George's Day / the 30th anniversary of the ZX spectrum "A doodle celebrating St. George's Day while faithfully representing the constrained technical capabilities of a 30-year old machine, ZX Spectrum, which was the early computer many people started on. (Someone subsequently dug out their childhood Spectrum and put our doodle on it!)"

  • Mark Ivey, Engineer

    Favorite Doodle: <a href="http://www.google.com/doodles/30th-anniversary-of-pac-man" target="_hplink">Pac-Man (interactive)</a> Occasion: 30th anniversary of Pac-Man "I'm a sucker for video games, and seeing how this doodle faithfully recreated the original pac-man even while re-making the map to be the Google logo was great."