It's hard to imagine Google without its spaghetti bowl of web services, but less than a decade ago it didn't even provide email. Gmail shook up the Internet when it entered beta on April Fool's Day, 2004, offering handy features such as threaded conversations as well as a whole gigabyte of storage -- 20 times what you'd get for free elsewhere. The catch at the time, of course, was that you could only get in with an invite, which promptly flooded eBay and commanded a premium of more than $100 at one point.

With its luxuries, it didn't take long for Gmail to attract a following. As of last year the service was used by nearly half a billion people across 57 languages and according to comScore, it has overtaken Hotmail as the world's top email provider. Celebrating that success and the iterative process it takes to achieve, Google has commemorated Gmail's ninth birthday with an infographic mapping the service's lengthy list of milestones, from the day it dropped invitations in 2007 through exiting beta in 2009 and beyond: