The Google home page is sporting the special logo above, celebrating the company’s ninth birthday, with one of the Gs turned into a nine. But wait? Didn’t Google just turn 10? Google Is 10 Years Old? Finding The Real Google Birthday that I posted earlier this month covers how yes, Google’s domain name turned 10 years old on September 15, but the company itself celebrates its incorporation date in September 1998. But when is that incorporation date: Sept. 7 or Sept. 27?

Google has celebrated both dates in the past, using Sept. 27 more lately, such as today. Wikipedia says Sept. 7 is the incorporation date but provides no reference to prove this. Google itself also provides no guidance that I can find. The California Secretary Of State’s company search tells me that Sept. 4, 1998 is when the papers were filed. So color me puzzled.

Want to see the past logos? Google’s been doing them since its fourth birthday, and Google Is 10 Years Old? Finding The Real Google Birthday lists them all. Here’s today’s logo again, in context of the entire page:

Related Topics: Google: General | Stats: History

About The Author: Danny Sullivan is editor-in-chief of Search Engine Land. He’s a widely cited authority on search engines and search marketing issues who has covered the space since 1996. Danny also oversees Search Engine Land’s SMX: Search Marketing Expo conference series. He maintains a personal blog called Daggle (and maintains his disclosures page there). He can be found on Facebook, Google + and microblogs on Twitter as @dannysullivan. See more articles by Danny Sullivan