Google doodle heralds the company's 13th birthday

As you may have gathered from its party-themed doodle, Google is celebrating its 13th birthday, a period which has seen the company rise from a simple research project to one of the biggest entities in the world with fingers in every pie.

Although Google likes to claim the 27th of September as its official birthday - making the advertising giant a mere teenager today - its origins stretch back further. The company was officially incorporated on the 4th of September 1998, while the iconic Google.com domain name - a deliberate misspelling of 'googol,' or a one and a hundred zeros - was registered a year earlier on the 15th of September 1997.

Google's true origins come from a research project dubbed 'BackRub,' created by then-PhD students Larry Page and Sergey Brin as a means of trying out a new method of finding suitable content by counting link-backs, rather than simply the number of times a search term appears on the page.

Page and Brin weren't the only people thinking that traditional search engines were prone to gaming: Robin Li had developed a similar system prior to BackRub dubbed RankDex. Although small, RankDex - and the patent it inspired - would go on to power Li's hugely successful search venture Baidu, which has been instrumental in keeping Google locked out of the lucrative Chinese market.

Realising that they might just have something special on their hands, Page and Brin registered the Google.com domain on the 15th of September 1997. Prior to that, the site had been running on a Stanford University subdomain. With a more professional web presence, Google grew to the point where the pair attracted attention and received its first injection of funding - a $100,000 cheque from Sun Microsystems co-founder Andy Bechtolmsheim - in August 1998, leading to its official incorporation on the 4th of September.

It didn't take the pair long to burn through that first injection of cash. After a failed attempt to sell the site to Excite - one of the biggest web portals of the 90s - for $750,000, Google announced on the 7th of June 1999 that it had snagged an impressive $25 million in venture capital funding from the likes of Kleiner Perkins Caufield & Byers and Sequoia Capital.

It would be another five years before the company needed more cash, launching an initial public offering using a unique auction format powered by Morgan Stanley and Credit Suisse, selling 19,605,052 shares at $85 per share for a market cap of over $23 billion.

Google's massive growth over this period meant it outgrew its home - a garage in Menlo Park, California - forcing a move to Palo Alto, home to many Silicon Valley startups including the famous Xerox Palo Alto Research Centre, or PARC. The year 1999 also saw one of the biggest fundamental changes to the way Google operates: a decision to capitalise on its success by selling keyword-powered advertising.

Initially resisted by Sergey and Brin, who still saw Google as a search company, a move into advertising is possibly the greatest decision the company ever made: these days, the majority of Google's income comes from its in-house advertising platforms, and the cash has been used to acquire companies including 3D mapping specialist KeyView, mobile startup Android, and advertising giant DoubleClick among - many - others.

Today, it's estimated that Google operates over a million servers across the world serving around a petabyte of user-generated content every hour, and has fingers in almost every pie: thanks to numerous acquisitions, the company works in search, advertising, streaming media, operating systems, mobile platforms, payment processing, location tracking, social networking, productivity suites, cloud-based computing, voice and data communications, scheduling, image editing, programming, mapping and translation services to name but a few.

Perhaps its biggest achievement, however, was to become a verb: like Hoover before it, a generation has grown up 'googling' things rather than searching for them.

It hasn't all been plain sailing, however: despite an unofficial motto of 'Don't Be Evil,' the company has come under fire for some of its schemes. During Apple's 'Locationgate,' Google was found to be tracking users with Android handsets, while its StreetView cars were - accidentally, the company claimed - recording traffic from Wi-Fi routers they encountered along the way.

Despite concerns as to the level of information the company stores on its users - information which is fed directly back into its advertising efforts, customising content in such a way as to practically guarantee a click or two - Google continues to grow. With 13 years behind it, things seem set to give the company a very successful 13 more - at the very least.

Editor's note:
Despite today being Google's 'official' birthday we can't fathom out why. That is, nothing we know of happened at Google on the 27th of September 1998 to make it worth celebrating. We've asked Google to explain itself, until then we'll assume it's like the Queen and has an official birthday as well as a real one. If you know better, do tell in the comments below...